Swiftech MCP 600 Pump Operating Voltage

[DNA]

What is the maximum operating voltage of this pump? I'm using the NexXxos XP and wonder if it is worth the effort to build a compact dc-dc converter. Would there be a marked improvement in cooling efficiency if I operate the pump at a higher voltage and what might that voltage be?

[Jimbo Mahoney]

Hey there,

I too have the Nexxxos XP block and AQX 50Z (MCP 600), although I'm running two of them in series.

The impression I get from Cathar is 13.5v is ideal for these pumps, and 14v is OK.

I WAS under the impression running the pumps with more than 12v wouldn't be worth it for the cost, BUT I've just found a 13.8v 3A DC power supply for £15 (I'm in the UK), so that is a very tempting option.

In fact, I'm sold.

I'll do some flow tests at 13.8v soon and let you know.

I got exactly 6 lpm through the Nexxxos with the two AQX @ 12v. That was with the nexxxos only.

[DNA]

Originally Posted by Jimbo Mahoney

Hey there,

I too have the Nexxxos XP block and AQX 50Z (MCP 600), although I'm running two of them in series.

The impression I get from Cathar is 13.5v is ideal for these pumps, and 14v is OK.

I WAS under the impression running the pumps with more than 12v wouldn't be worth it for the cost, BUT I've just found a 13.8v 3A DC power supply for £15 (I'm in the UK), so that is a very tempting option.

In fact, I'm sold.

I'll do some flow tests at 13.8v soon and let you know.

I got exactly 6 lpm through the Nexxxos with the two AQX @ 12v. That was with the nexxxos only.

Yes, I would be interested in the results. Also, do you have any feel for what the C/W is for your system and what is your configuration? Unlesss you have plenty of room, have you considered a variable dc-dc converter, space wise that could be as small as 2-in x 2-in x 1-in?

[Jimbo Mahoney]

Hey there DNA,

I don't have a system as yet. LOL.

I'm building the cooling system first, then buying the actual hardware.

Space is NOT an issue for me since I will be running an open desktop case with the rad, pumps and res external.

The configuration is:

Res / air-trap (home-made) 5/8" -> 1st AQX -> 1/2" 2nd AQX -> Nexxxos -> Fusion HL GPU -> Custom low-flo Nbridge block for DFI NF4 -> split to 1/2" bypass and Silentstar HDD Dual + 3/8" MOSFET block -> car Radiator (40cm x 30cm core) -> Res

When the flow splits, I mean one branch will literally be just a 1/2" pipe, the other branch will be 1/2" to the Silenstar and then 3/8" to the MOSFET block. This will mean minimal flow resistance, but also not much flow to the MOSFET or HDD, but they hardly need any flow anyway.

As yet, I have no idea of the C/W, not having anything to hook it up to! I am prepared for the estimation though, with 4 probes to measure CPU die temp, GPU die temp, water temp and air temp.

I'll be posting a full run-down when I get it all running in a few months' time.

[DNA]

Originally Posted by Jimbo Mahoney

Hey there DNA,

I don't have a system as yet. LOL.

I'm building the cooling system first, then buying the actual hardware.

Space is NOT an issue for me since I will be running an open desktop case with the rad, pumps and res external.

The configuration is:

Res / air-trap (home-made) 5/8" -> 1st AQX -> 1/2" 2nd AQX -> Nexxxos -> Fusion HL GPU -> Custom low-flo Nbridge block for DFI NF4 -> split to 1/2" bypass and Silentstar HDD Dual + 3/8" MOSFET block -> car Radiator (40cm x 30cm core) -> Res

When the flow splits, I mean one branch will literally be just a 1/2" pipe, the other branch will be 1/2" to the Silenstar and then 3/8" to the MOSFET block. This will mean minimal flow resistance, but also not much flow to the MOSFET or HDD, but they hardly need any flow anyway.

As yet, I have no idea of the C/W, not having anything to hook it up to! I am prepared for the estimation though, with 4 probes to measure CPU die temp, GPU die temp, water temp and air temp.

I'll be posting a full run-down when I get it all running in a few months' time.

Looking forward to your future post.

[MadHacker]

did some quick searching on google
found this
13.5 VDC 2.4A ADAPTOR $4.50
somthing to think about...
I have 2 MCP600 as well...
I'm just curios how much louder it will get...

[DNA]

Originally Posted by MadHacker

did some quick searching on google
found this
13.5 VDC 2.4A ADAPTOR $4.50
somthing to think about...
I have 2 MCP600 as well...
I'm just curios how much louder it will get...

If you don't mind the fact that it is an AC-sourced supply, it may be a very cost effective solution for a single MCP600. You may be pushing its current capability limits with (2) during power up.

[MadHacker]

Originally Posted by DNA

If you don't mind the fact that it is an AC-sourced supply, it may be a very cost effective solution for a single MCP600. You may be pushing its current capability limits with (2) during power up.

for the price of them....
buy 2 for 2 pumps.

[DNA]

Originally Posted by MadHacker

for the price of them....
buy 2 for 2 pumps.

It is a great price, agree!!

[Risky]

I modded a DC/DC stepup powersupply to give 12-24V on a pot, however you could definitely adjust this to max out at 13.5V if you used a preset pot for the minimum resistance on the control line.

[TbirdX]

I'm planning to run my MCP600 @ 13.6v. Mainly because I got the PSU from work for free

[MadHacker]

Originally Posted by TbirdX

I'm planning to run my MCP600 @ 13.6v. Mainly because I got the PSU from work for free

can you let me know how much louder the pump is runnning at 13.6v compared to 12v?

[TbirdX]

Well not really tbh. It's new (to me) and I'll be running it at 13.6v from the off. According to a post by Cathar though, he says it's not much, if at all, louder at 13.8v than at 12v.

[Jimbo Mahoney]

Hmm, bad news from me re: PSU:

The PSU I bought says not to use it with motors, lightbulbs or charging batteries!!!

I assume this means it uses PWM or something to give the 13.8v DC?

I assume also that this also means I can't use it with my AQX pumps?

[Butcher]

Cathar has numbers for 13.8V operation of the MCP600, it gives a good boost.
See this thread.

[Hoot]

That's a great article, but it leaves me in a quandry about something. I ordered a G5 based upon PHaestus article showing it yielded CPU temps ~7.9-8.1C above water temp at the right flow rate. I contrasted that to what he said the Cascade yielded ~9.5-10C above water temp at the right flow. Now, reading the previously linked thread, Cathar says he got the following with the Cascade:

Let's rank it for easier browsing shall we?

+20.8C => 2 x Swiftech MCP600 @ 13.8v (series)
+20.9C => Swiftech MCP600 @ 13.8v
+21.1C => Iwaki MD-20RZ @ 60Hz
+21.1C => 2 x Swiftech MCP600 @ 12.0v (series)
+21.2C => Iwaki MD-20RZ @ 50Hz
+21.4C => Swiftech MCP600 @ 12.0v
+21.4C => 2 x Eheim 1048 (series)
+21.5C => Iwaki MD-15R @ 60Hz
+21.6C => Swiftech MCP650 @ 12.0v
+21.6C => Iwaki MD-30RZ @ 50Hz
+21.7C => Iwaki MD-30RZ @ 60Hz
+21.9C => Eheim 1250
+22.3C => Eheim 1048
+23.3C => Eheim 1046

Who's water to CPU temperature differential is the right one for the Cascade?

Hoot

[Cathar]

Originally Posted by Hoot

That's a great article, but it leaves me in a quandry about something. I ordered a G5 based upon PHaestus article showing it yielded CPU temps ~7.9-8.1C above water temp at the right flow rate. I contrasted that to what he said the Cascade yielded ~9.5-10C above water temp at the right flow. Now, reading the previously linked thread, Cathar says he got the following with the Cascade:

Who's water to CPU temperature differential is the right one for the Cascade?

Hoot, there are large differences between the two examples.

Phaestus is taking an actual CPU-die to water-in temperature delta based upon a T'Bred B CPU (~88mm^2). It has been postulated that while Phaestus has quite accurately calibrated the on-die diode of the CPU die, that the diode is actually located in a rather cool section of the CPU die (towards a corner would be my guess, just as is true of P4 CPU dies), so the reported temperatures are somewhat "compressed" because sections of the CPU die will be a lot warmer than what the on-die diode is reporting.

The numbers I was calculating was based upon a projected estimate C/W curve for a Cascade block given a 100W 10x10mm heat source derived from a combination of Phaestus's, BillA's, and my own data. The curve that I used was not directly emperically obtained, but rather a theoretical curve that attempts to remove Phaestus's postulated temperature compression from the results he obtained, and my own results, and massage it into something that is somewhat comparable to BillA's old waterblock data. It is a fantasy curve though - make no mistake. For what it's worth, the results that I obtain for my own blocks, after a bit of pseudo-calibration with a 101mm^2 Barton CPU die, closely reflect the same flow vs C/W results that BillA obtained on his 100mm^2 CPU die test-bed, however the equipment I use is nothing in comparison to quality kit that Bill and Derek are using, so frankly I consider any correlation to myself and Bill's result to be more a result of pure chance than anything else.

The values I listed are the CPU die to ambient air differential, and include the pump heat effect, as well as the impact of the flow rate of each pump on the efficiency of the radiator (Thermochill 120.2 model was used) and the waterblock (based on the derived performance curve).

Given the results that both Bill obtained with the White Water, and what I measured, and again with what I measured with the Cascade, I would "suggest" that the values that I gave are perhaps closer to an accurate picture of what the hotter sections of a fairly heavily overclocked CPU die are approaching, but again, this is a mish-mash of extrapolations and corrections using woefully inadequate equipment, yet which somehow still manages to serve the purpose well enough for me to develop waterblocks with a fairly high degree of (perhaps misplaced) confidence.

[Hoot]

That explains it. Thanks for taking the time to elaborate on that Stew. I eagerly await the second notice that the G5s are ready to ship! Meanwhile, I'm still wrestling with getting the darn blocks to sit perfectly flat on the die repeatedly. Harder than it sounds for some reason, but I'm resourceful. I'm going to look into the chance that the tapped ferrules connected to the backing plate, which the mounting screws go into may not be perpindicular to the backing plate tonight.

Regarding Bills testbed. I have great respect for it also. The only place I diverge from it is the fact that in using a copper extension of the copper body as a die simulator, versus the (assumed) silicate that typically is used in a CPU die, does not repersent the same source impedance of the heat energy. Examined as two separate worlds, they are great, but I personally am more interested in a testbed that simulates what I will encounter in real use, versus the ideal independent testbed. I do not look for a direct correlation between the two testbed results degree for degree, but more in the direction of trends.

As you know, we're about at the end of our rope with ambient cooling, until some major seachange occurs in the TIM barrier. I forget where I read it, but I saw a web site with a hybrid passive and active transport IHS, using imbedded, multi-dimensional path TEC technology. Sounded good, at least in concept. Another site talked about something I've pondered for some time. Using a slurry cooling solution with suspended microparticles of a substance that had 2-3 times the heat carrying capacity of water. That still would not help with the TIM barrier issue. Lastly, I wish I had the tools necessary to experiment with sintering copper or silver. I have some ideas about a baseplate with a sintered surface on the water side that is impermeable on the die side. Maybe it's already been tried...

I'm always looking for better hardware and if I could find a pump, either AC or DC, that ran as quiet as my 1250, but with significantly higher performance, I'd probably pick one up. Been watching the Iwakis on Ebay, but the Walchem/Iwaki site does not list sound pressure ratings for their pumps. That MD30rz-No7 looked tempting earlier today but I do not have enough knowledge about the sweet spot between wattage, noise level and raw capacity to make an informed investment yet.

Hoot

[DNA]

Originally Posted by Jimbo Mahoney

Hmm, bad news from me re: PSU:

The PSU I bought says not to use it with motors, lightbulbs or charging batteries!!!

I assume this means it uses PWM or something to give the 13.8v DC?

I assume also that this also means I can't use it with my AQX pumps?

I've found a Mean Well DC-DC Converter that was price quoted at $23.61 plus shipping. Its physical size is slightly less than 4-in square and is ~ 1.4-in in height. It's about 2X the size that I had planned for, but I do have plenty of room in my Lian Li PC75 case. The Mean Well model designation is SD-25A-12 and it is rated at 25.2W, 2.1A @ 12V. Input voltage range is 9.2V to 18Vdc. Adjustable output voltage range is 11V to 16Vdc, which is ideal for a single Swiftech MCP600. I would be operating the pump at 14.0V which should require ~ 15 to 15.5W.

Link to supplier's website:
http://www.cdiweb.com/PortalProductD...d=258354&fmt=1

[Jimbo Mahoney]

Hey DNA,

I'm in the UK and I can't be bothered to order a PSU from outside the UK.

The only reason the PSU I have isn't suitable is (I'm assuming) it outputs varying DC. Luckily, I have an oscilloscope at work, so I'll see what its output is like.

Reading up a little on Regulated PSU's, it seems I just need to add a decent value capacitor to the output to smooth it enough for the pumps.

Any ideas if this is correct and if so, what value capacitor? I was thinking 2200uF. (guess)

[Hoot]

Originally Posted by Jimbo Mahoney

Hmm, bad news from me re: PSU:

The PSU I bought says not to use it with motors, lightbulbs or charging batteries!!!

I assume this means it uses PWM or something to give the 13.8v DC?

I assume also that this also means I can't use it with my AQX pumps?

Jim;

2200uf would be an excellent choice. Not knowing why the company that makes that power supply would caution against using it with certain appliances is an enigma, but you're probably correct in assuming they skimped on the filtering capacitance. Many "wall warts" fall into that category, but usually the capacitance they provide only falls short if you draw near the maximum rated current. Nevertheless, I'd bet a 2200uf capacitor would suffice. You may have to parallel a couple of small values with the 2200 to cover any high frequency components in the output waveform, like a .01uf, .1uf, and 1uf. Maybe not. You're lucky to have access to an oscilloscope. They're great tools.

Hoot

[Jimbo Mahoney]

Hey Hoot,

Thanks.

I'll hook it up to an oscilloscope with and without a capacitor.

I read further here:

http://www.kpsec.freeuk.com/powersup.htm

And found a calculation for the capacitance required. It seems at 5A (the max current supply for my PSU) I need 3600uF, or 1800uF at 2.5A (the continuous current for my pumps).

So I guess 2200uF will be perfect.

[Jimbo Mahoney]

I found the circuit diagram for the power supply:

http://www.maplin.co.uk/Media/product_pdfs/XM22.pdf

It looks like it only has a 10nF cap on the output side, so I presume it gives mediochre 'smooth' DC out the end?

[Hoot]

10nf wouldn't do diddly for filtering, but the 220uf next to it should help at low current draw. You're right in adding some additional filtering. Odd though, batteries love pulsating DC, light bulbs don't much care, but motors might be fussy about it.

Hoot

[Jimbo Mahoney]

Right, I hooked it up to the oscilloscope (my colleague kindly offered to let me take it home if I want to test some more).

Now, with NO LOAD, the output is very good and only seems to vary by 20mV, maybe not even that.

Sadly, I don't have anything I can load the thing with here, I'll have to hook it up to the pumps at home and see what the output is like then.

Maybe the PSU manufacturers are just covering their backs by limiting its use?

Also, back to the original question, what is the maximum operating voltage of the AQX / MCP600 pumps? Using that circuit diagram, I found the VR I need to adjust the output voltage of the PSU - it can be varied from 12.15 -> 15.25, so I could run the pumps higher than 13.8, but what is the max safe voltage? I'd be assuming in the region of 14.4, but that's just an 'educated' (hehe) guess.