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General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums. |
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#1 |
Cooling Neophyte
Join Date: Mar 2002
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I have read many posts from this forum (as well as the [H], AMDMB, and Overclockers) about the advantages of larger tube sizes (everything 1/2 ID). Yet the only comprehensive benchmarks I've seen regarding Waterblocks has been at Overclocker's .
If you look at the top rated WB, it is the Innovatek which uses a block that has only 10mm OD (8mm ID) tubing, has an Eheim 1046 pump, and a crappy radiator (Heatercores and even BI rads are better). So I have two questions, First, does anybody know of a review on the newer Maze 3 (uses 1/2 ID tubes I believe)? I know according to Birrman54 in the [H] forum that he is going to do a Waterblock roundup with both the Eheim 1250 and 1048 pumps (not sure about tubing size though), which will include this block as well as several other popular blocks. My Second question is tubing size, has anyone done a performance review of various tubing sizes as related to performance? I know that the WB and Pump would probably affect this kind of review, but might be worthwhile to everythone to actually see some numbers (instead of some of the ranting I have seen done in all of the forums on this subject). Thanks for the help. |
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#2 |
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Unaclocker (who used to post here) swapped his 3/8 for 1/2 and saw ZERO difference. The extra flow in the waterblock was negated by the fluid passing too fast in the rad.
I have yet to see a Maze3 review. |
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#3 |
Cooling Savant
Join Date: Feb 2002
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honestly, i would need more than one review / roundup to make a decision as to what block is best, etc. unfortunately, i havent found any reviews other than what Overclockers and ProCooling has posted. PC is supposed to continue their WB roundup with the AMD waterblocks (Maze2/3, spir@l, etc etc), but Joe doesnt seem to have time to do that at the moment.
so, nope, i dont know of any articles..... and as far as what Ben said, unless una had flowmeters testing the flow rate befor and after the tubing swap, id take that comment with a grain of salt (not that i dont believe him, but we need hard numbers here) |
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#4 |
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I agree CD, we need more numbers.
Now that you mention it, simply swapping hose size shouldn't make a d*** difference, simply because most of the resistance is within the WB. Una (not here anymore) said that his flow rate increased 400% (how did he know?). OC has numbers too... |
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#5 |
Big PlayerMaking Big Money
Join Date: Aug 2001
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You don't need more low quality numbers and testing. What is really needed is a little more theory on heat transfer, fluid mechanics, and flow through pipes and fittings. That will give you some perspective on "the big picture"; there is no way to fully optimize flow and water velocity in every person's setup with a waterblock (or radiator, fitting, pump, etc) roundup. It is just too complicated a problem. However, to some extent the numbers are there if one looks at them in Joe's waterblock roundup. For the most part, flow rates of 0.5-1 GPM are typical with ~200GPH rated pumps and 3/8" setups. For 1/2" setups and the same pumps then 1-1.5GPM is more normal. Look at Joe's temperature vs. flow data and for each block you can get a reasonable idea as to how it will handle lower or higher flow rates. You can also see for most of the blocks that there is a 1-3C improvement in the range of 0.5 to 1.5 GPM.
Here is some old data of mine when I first got a flowmeter. This data doesn't have the proper resolution (I am nearly ready to start testing blocks now though with much better temp resolution and decent water temperatures finally), but it shows the general trend: ![]() Comparing the block vs water temp would be better, but since the pump puts more heat in at lower flow rates (it was throttled with a ball valve) then this graph might perhaps give a better estimate of "overall system performance". I personally am more interested in block performance only at the moment... |
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#6 |
Cooling Savant
Join Date: Dec 2001
Location: Nebraska
Posts: 526
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Has anyone ever checked out all the data here:
http://www.dansdata.com/coolercomp.htm I find it quite interesting, and all the tests are done the same.
__________________
========== --Soyo KT333 DRAGON Ultra (Platinum Edition) --AMD 1.4 @ 1.54 (11x) --768mb of PC2100 (@140FSB) --Asus v8200 GeForce3 @ 210/490 --Maxtor 40gb Quiet + 2 IBM 40gb 60GXPs (removable) + 8gb WD --Audigy --Maze 3, DD Gf3 block, 2x BIX, Eheim1250 =========== |
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#7 |
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Thanks PHaestus, I've always been a proponent for more theory.
I see your graph, and it seems to indicate what every reasonable OC'er has been saying (more is not better). I've read MANY articles, and I plan to read them over again a few more times. Test conditions are very important, and in my opinion, if one can't evaluate the margin of error in a setup, then the data has little value. (but the theory might be) From your graph though, I would advance this theory: an increase in flow rate will generate better heat dissipation from the waterblock, but MUCH less dissipation from the radiator. I'd like to see someone test different flow rates with a Big Momma, then try the same test with TWO Big Mommas in parallel. (maybe I should ask Miss_Man?!? ![]() I'm also starting to consider copper tubing (instead of silicone/vynil/Tygon), or even better, finned copper tubing... WebMasta33, yes, Ive seen Dan's data. The numbers aren't reliable (although they are consistent), but the ideas that he advances are great. (Ooh check out that OCC!). The heat source is what makes Dan's data relevant. Under ideal circumstances, one would figure out a way to supply water at a fixed temperature (maybe using one of those thermally controlled valves used in photo labs), so that the testing of a waterblock wouldn't depend on anything other than itself (i.e. there would not be any external factors affecting the performance test). Of course this means dumping the water out during the test, so unless you have one of these, you're looking to run up quite a bill... |
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#8 |
Big PlayerMaking Big Money
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Careful; you are reading a lot into a graph that has low resolution and perhaps isn't the best anyway. The thing I would really feel comfortable with saying for most of the blocks we use is that if your flow rate is below 1GPM (which it probably is using 3/8" tubing) then there is a fair amount of performance that you can gain by switching to 1/2" fittings. You could also probably get nearly the same effect by just drilling out your existing 3/8" barbs as much as you can.
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#9 |
Cooling Neophyte
Join Date: Mar 2002
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Nice to see all the support in this forum.
As to the debate on testing, I don't think there will ever be one clear solution on this. To be honest, I would like to see an overclocked AMD system (maybe at 2.1v) with just standard watercooling stuff. Having something that generates gobs of heat to test the system isn't realistic. As is using a constant flow of the same temperature water. Both of these would give a best worst/best case scenario and nothing real world. My Ideal test setup would be something like this... 1. A system with a AthlonXP overclocked and overvolted which should generate some good heat (as well as performance ![]() 2. Installed in a common case type (Antec would be good I suppose, but really any good Mid-Tower should work), with standard fans installed. 3. In a room where the temperature could be monitored, but with the case closed up (not opened which could skew the numbers). With this setup you would have a fairly common setup (similar to the various Heatsink roundups you see done on the various websites). Now you could setup a baseline system (say a Maze3, with 1/2 ID tubes, connected to a heatercore, and an Eheim 1250 pump). Block Testing: Once you have the baseline numbers, you simply can swap out different Blocks to test them with this setup. Pump Testing: Once the various blocks are tested, you could change the pump to a 1048, or 1046 and perform the tests again (which would give you a good baseline on pump performance). Tube Testing: Now simply change the hoses to say 3/8 ID (or smaller) and do the same tests again. Radiator Testing: Just as with the other tests, you could just change the Radiator (BIX, BI, DangerDen, Heatercores, etc), and record what the benefits are for each one. This is my opinion, but I think this test would be more realistic to a lot of people. Just a thought, what do you all think? |
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#10 |
Big PlayerMaking Big Money
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If you can't control the variables and you can't measure them with any certainty then you will end up seeing whatever you want to see. I have a testbed that is about as good as one can have that is still "real world", but I would still prefer to eliminate the radiator from the equation and use something to provide a constant inlet temperature. Simulators are used in place of processors when people want to actually quantify the power (and heat) that is going into the system. That is really the only way to compare different heatsinks or blocks.
If you look at AMD's technical documents, they use die simulators that are very advanced (monitor heat in several places) and do not bother with socket probes to draw their conclusions. Why wouldn't you expect the same from an "expert" reviewer? |
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#11 |
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PowerHouse: I completely disagree with you, and on more level than one! But I do agree that testing on a typical computer is necessary.
Now, here's why I disagree: 1- The existing line of CPU's constantly change, so to keep the same testing rig throughout all tests would NOT give us a result for the greatest/latest computer. You know how fast they go out of style... I still use a Pentium 166!!! (among others) 2-CPU temps can vary, depending on the load that is put on them (regardless of over-volting). You can argue that one can use some benchmarking software, but the problem is that every computer configuration is different, and I've seen too many people run the test, then read the temperature right away and report it, when in fact, a completely assembled system could take many hours to stabilize. (One factor is the volume of water) 3-That being said, given the choice between using a $750-$1000 system to test, which has to be dedicated for that purpose, with the hope that it will never break down VERSUS using a $25.00 high-power resistor, a power supply, and some measuring instruments (flow-meter, temp probes, volt meters, etc...) Well, you do the math, and honestly tell me which one you would trust the most. 4-Given the above info, and what you propose, you need to understand that the time required to test all those configurations would take days, if not weeks, and that sometimes, the guys reviewing that stuff, don't have the item in their hands all that time. 5-What you are proposing comes down to testing a complete configuration, not an individual component. 6-The pump: it's very simple, use an industrial (or big) model, slap a flow restrictor, and a flow sensor, along with a pressure gauge. This would allow for a lot more usefull data, and would be much simpler than trying to install different pumps. As for testing a pump, the specs are already available everywhere, so don't see the point in testing them, except for reliability, and mods. The rads: setup as above (pump with flow limiter, a standard block and a standard heat source). Tubing: tubing doesn't really need to be tested. The only thing a bigger tube will do, is add water mass to the system, and ease flow, but it's so insignificant compared to elbows, and most importantly the flow resistance in the water block (greatest of all) that it's not even worth mentionning. You're also forgetting that regardless of the optimal setup someone puts together for a "typical" system, as you would put it, there may be other configurations that could be just as effective (i.e. a DD Maze3 with a BIX versus a Gemini HF-spiral with a Big Momma). The thing to keep in mind, is that people like to have a choice. I'd rather know that I can get a Swiftech with a Bix, using an Eheim 1048, because the optimal flow rate of each component is the same. Now if there is someone out there than can do all that, THEN test it in a typical (at press time) system, then I would worship them! |
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#12 | ||||||||
Cooling Neophyte
Join Date: Mar 2002
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#13 | |
Cooling Neophyte
Join Date: Mar 2002
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If you eliminate the radiator from the equation, then you actually skew the numbers as this wouldn't be a real world situation (at least I haven't seen anybodys watercooling rig without a radiator). So in effect you would be saying, that given a constant temperature water (hmmm, what would you consider a normal temperature for water?) WaterBlock-A can keep CPU-X at Y temperature while WaterBlock-B functions at Y+5 degrees. While this sounds like a good test, what you may miss is, that given a higer water temp, WaterBlock-B may be able to keep the CPU-X temp at it's original temperature, but WaterBlock-A actually could perform worse. |
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#14 |
Big PlayerMaking Big Money
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I have heard a lot of talk about birrman's roundup, but have not seen any information about how he proposes to actually test the blocks or what equipment he is using. I am soon to start on the second Pro Cooling waterblock testing, which will (due to time and money constraints) be limited to a few popular blocks. If you are interested in my testbed, I am using:
1) Little Giant 3E-12NYS industrial pump. This is a big unit (200W heat but ~7.9 PSI) 2) flowmeter from mcmaster. This is in need of upgrade; it really affects the flow rate and is not digital so think of it as a crude approximation. I am still looking for a good replacement. 3) Water and air temperatures: wb inlet and outlet temps taken with Dallas 1-Wire probes that have been sealed with silicone and placed into 1/2" NPT caps. Radiator intake and outlet and also room temperature taken also with DOW sensors. Specs are 0.5C accuracy and 0.125C resolution. CPU temperature: AMD Duron 1.0 (Morgan) at 1200MHz 1.9V (or more if I get around to vmod). CPU under temperature taken with DOW sensor epoxied under center of core. AMD diode readings taken from a MAX6655EVSys diode reader that interfaces with a computer via parallel port. 1C accuracy and 0.125C resolution on this one. Pressure Drop: DPT measurement setup that I still have to get running. I will use PVC crosses to put the DOW temp probe and the DPT setup close to the wb inlet and outlet. This all sounds terribly impressive, but the temperature readings are still not really that great (I really want 0.1C ACCURACY) and it is sort of a bastard setup in that it is higher quality than most general users are willing to put together but it remains much poorer than what is really needed. In the next few months I will likely upgrade the flow sensors and add a recirculating water bath to keep the water at exactly constant temperature (we have a VWR unit in our lab that I may try to appropriate if it keeps making strange noises). The temperature monitoring is troubling and will be very expensive to do right. I am for now satisfying myself with doing the best job I can with the equipment I have (replications, careful variation of flow rates, minimizing errors) and I figure the most pressing upgrade needs will be obvious once my test methods are established. |
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#15 | |
Big PlayerMaking Big Money
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#16 | |
Thermophile
Join Date: Jun 2001
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Heres my theory. Everyone can afford $17 for a heatercore (or a Blackice) that has 4x the cooling power they need. Therefore radiator and pump dissapation are not particularly important. Furthermore the thermal resistance of copper is fixed. Therefore no matter how much you flow you can only approach a given effciency with a given design. Thats why more flow will eventually not yield more performance, but not because of radiator effciency. |
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#17 |
Big PlayerMaking Big Money
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![]() ![]() That might change the discussion a little... |
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#18 |
Cooling Savant
Join Date: May 2002
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To redleader, radiator efficiency is much like block efficiency. However, the relationship tends to be reciprocal. Imagine a radiator in which the water exited a mere second after it entered. There would be insufficient time for the water to approach the temperature of the air blowing over the radiator. On the other extreme, imagine a radiator where the water required ten minutes to get from entrance to exit. Upon exiting, the water would essentially match the air temperature. Each of these extremes would not exist in a computer cooling setup, but illustrates the concept involved.
This is the catch-22 of water cooling. Blocks perform better with high water velocity, yet radiators perform better with longer dwell time. In pHaestus' graph, you see the effect in a block. As flow approaches zero, the differential between the CPU and fluid grows as 1/flow. As flow increases, the differential follows this same 1/flow trend. If a similar graph was plotted for radiators showing the differential between fluid and air, you'd find a relationship that is the reciprocal of that for the block. ie 1 over 1/flow = flow. As flow rate in a radiator drops, delta T drops. As flow rate through the radiator increases, delta T increases. There is no magic in stating that blocks do well with high velocity while radiators do well with low (water) velocity. What more folks need to recognize is that velocity is not simply a function of volumetric flow rate. Velocity is volumetric flow rate divided by flow area. Blocks that utilize (properly defined) small flow paths can meet or exceed the performance of blocks using substantially larger flow paths (and correspondingly higher flow requirements). The kicker here is that a block with small flow pathways and low volumetric flow rate yields better radiator performance that a high flow block with all other components held constant. It does this simply because the lower flow of the former block creates more dwell time for the water in the radiator. A corollary to this concept is that you can get equal performance from a smaller radiator using a low flow block when compared against a big radiator and big block. Make no mistake, to realize such a result requires proper design of the block and proper selection of the pump, radiator, radiator fans, and tubing. Unfortunately, the majority of water cooling users seem to blindly follow the "bigger is better" theory without regard for the interactions that take place between the block and radiator. |
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#19 |
Cooling Savant
Join Date: Nov 2001
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increased flow in a radiator does decrease cooling capacity. i am not nearly as advanced as those who have spoken above, but the graphs in BillA's test show that most radiators lose cooling capability at higher flow, except for two. the big momma he tested, did lose some, but not much, dissipation capabilities. the serck he used increased dissipation as flow was increased. you can see it here:
http://www.overclockers.com/articles481/index05.asp its the third graph down. as you can see, the big momma didn't lose much as you increased flow. the serck, with more air flow, increased dissipation as you increased the flow. i can't comment on his testing procedures, and if it would satisfy you guy's standards however. although i do remember him as being a pompous advocator of testing methods. |
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#20 | |
Cooling Neophyte
Join Date: Mar 2002
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So in the example I have given, WaterBlock-A might have a fast flow rate (Maze-3), while WaterBlock-B has a slower flow rate (Innovatek3). So give the constant water temp coming into the block (Say Room Temp of 70 degrees), the higher flow block would have a temp closer to the water coming into the block. While the slower flowing block would have a higher initial heat (as the water isn't moving fast enough to keep the block as cool). In a closed system (like the real world) with a radiator, the temp of the water will increase with the heatload generated by the CPU. Now because of the design of WaterBlock-A (fast flow, low water resistance - read less surface area), the water flows so fast that it doesn't have time to absorb all the heat from the CPU. While WaterBlock-B with it's slower flow rate (yet higher resistance - read more surface area) can release more of the CPU's heat into the water. This is where a good radiator comes into play. While WaterBlock-A's fast flow actually hinders the effeciency of the radiator, the slower moving WaterBlock-B gives the radiator more time to remove the heat. This is also why you see people needing larger radiators (Big Momma, etc), to keep WaterBlock-A cooler. Thus as the water heats up, WaterBlock-A actually performs worse than WaterBlock-B. But in your tests, you wouldn't be able to see this result as you would just see WaterBlock-A keeping a lower temperature. Again, this is why I stress realworld examples vs. Lab testing. Last edited by Powerhouse; 05-24-2002 at 12:40 AM. |
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#21 |
Big PlayerMaking Big Money
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You are again talking about testing a complete system and not evaluating the performance of any one item. There is no reason (based upon physics) that a block would perform unrealistically by controlling an inlet temperature. You are instead talking about radiator performance affecting waterblockperformance, which is precisely the thing you want to eliminate when testing either blocks or radiators!
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#22 | |
Cooling Neophyte
Join Date: Mar 2002
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![]() Think of it this way: If you heat up a frying pan, and drip water onto it at a slow rate, it will cool less than if you have a higher volume of water flowing over it. So in a test, the higher flow rate would always win. Not much of a test if you ask me. |
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#23 |
Big PlayerMaking Big Money
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The more seasoned testers of heatsinks either include multiple fans or vary the voltage of the fan to get an idea of how it will perform with different CFM through the cooler. That is the same principle here. Blocks always perform better with increasing flow rate, but how much better is not constant. By looking at performance curves for the different blocks and comparing them to your choice of pump and radiator, one would hopefully be able to make choices in parts that would lead to an efficient system that is performing at close to optimum levels. You also have the possibilty of developing a more coherent "big picture" sense of water cooling loop design than if you just test a lot of different complete systems and try to draw no larger conclusions from them.
Just because you seek real world results doesn't mean you have to eschew the fundamentals of science. Isolate the variables of interest and then vary them one at a time while holding others constant. Build up a model that effectively includes all the observations. That is science at its most fundamental level. That has nothing to do with a laboratory either; it is useful everywhere. Any time you have multiple properties varied though you can extract nothing useful from the results. |
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#24 |
Cooling Neophyte
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I'll answer this one in reverse order.
1. Pure science doesn't always work in the real world. Here's one example: People with Diabetes need insulin so their body can use sugar. However, when doctors were testing insulin on lab animals, all of the animals died. So being a scientist your first thought would be that insulin would be unsuitable for people to use. Hopefully you know that insulin is one of the treatments people take for Diabetes, and although it kills the animals it was tested on, it works perfectly in humans. 2. You kinda said what I have been trying to say (just harder to understand it I guess). "Blocks always perform better with increasing flow rate, but how much better is not constant. By looking at performance curves for the different blocks and comparing them to your choice of pump and radiator, one would hopefully be able to make choices in parts that would lead to an efficient system that is performing at close to optimum levels. You also have the possibilty of developing a more coherent "big picture" sense of water cooling loop design than if you just test a lot of different complete systems and try to draw no larger conclusions from them.' Although you could look at performance curves of different blocks, you still need to match them with the correct choice of pump and radiator (which is what I have been saying). If you just test the blocks, you would lead people to believe that the top performing block in your test is the best. However, this wouldn't necessarily be true, it would greatly depend upon the pump and radiator used with the block. Which leads back to my arguement that all three components need to be tested to find the best mix for the "optimum levels.' |
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#25 |
Cooling Savant
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When it comes to a radiator, a little bit quickly adds up to the same as a lot slowly as far as flow goes. It's how efficient the heat transfer in the block is that should make a difference if the radiator is not overloaded by being too small or bad airflow through it for example. Also getting the heat out of the block as quickly as possible will keep excess heat from being stored in the metal of the block. I think faster flow with the right radiator and block designed for it should be better than a low flow settup.
my $0.02:shrug: |
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