1/2 vs 3/8
 

Ok, age old question, but one I didnt see directly talked about here.

I am trying to decide on a 3/8 system or a 1/2 system. My plan is to have twin CSP-Mags (whenever they come out and if they prove to be as good as they say) drawing off of 2 custom reservoirs, with a DD TDX for 64 and a BlkIce extreme 120mm rad, and eventually a gpu and nb block, hence a somewhat overpowered system for a single block.

My leaning toward 3/8 is simply size and weight, my case is about average size and I like to be able to get in there and work on my system fairly easily without a lot of large tubes. This is also a box i take to LANs so obviously less water in the system the less weight somewhat.

The plan is to have as many high flow DD fittings as I can implement in the system, with the TDX having these as well as my res tanks when I build them, and the rad is 1/2 in either setup.

I was hoping some of you could really spell it out to me the advantages and disadvantages of both and personal experiences. Mostly I am trying to gather if the performance will really be the same with either setup. With the CSP mags they can be run in dual for either more pressure or more total flow, so I am trying to see what setup would suit what I want to do the best.

the obvious, 1/2" is less restrictive and 3/8" is easier to work with. i think someone did a comparison with the two sizes and found that there really was no difference. however, i do not recall what hardware they were using so it may or may not be relevant to you. nevertheless, if you plan to have three blocks, the smaller tubing might be the way to go unless you have a particularly roomy case. i doubt it'll hurt you seeing as how you'll be using two pumps.

Yeh, pretty much what Cyco dude said.

3/8" is only really a problem with poor low pressure (low head) pumps.

What's the head rating on those CSP Mags? Will you be running them serial or parallel?

3.2 psi, 140gph

Im not really sure on the configuration yet, with 3/8 i suppose being in parellel would get better overall flow.

Having dual pumps has makes the system highly configurable and dual loop capable, I think as long as I am going to radically mod my case this would be a nice way to do it. What I am thinking is having a twin tube res setup on top with each pump feeding off of one tube right below the tubes.

Naturally all of that would require a lot of tubing, 3/8 is looking more and more attractive. I just want to confirm what I think I already know with the best cooling site on the net 8)

Water cooling went to 1/2" when water blocks required high flow rates to acheive good cooling (ie, spiral designs).
These days the water blocks that perform best (LRR cascade G4 etc) work on pressure drop to deliver impingement, and work very well at lower flow rates.
Hence, 3/8th tubing is no longer a drama if you're using such blocks, and have "reasonable" tubing runs.
If you're desiring mega flow rates, or are running many meters of tubing to get outside etc then you may consider 1/2"

3.2 psi = 7.4 ft head.

I think you'd be better off running the whole system in serial.

Two of those in serial would give 15 ft head 140gph. A much nicer thing to work with than 7.4 ft head and 280 gph (pumps in parallel).

Having said that, what do you plan on cooling?

If it's a single CPU block requiring high-flow, the parallel pumps may be better.

Otherwise, I'd run the whole lot serial and get decent flowrates due to the nice pressure you've established with the two pumps in serial.

Someone correct me if I am way off here...

Any way you could change the fittings on the BIX to 3/8" (assuing that's what you'll use)? It isn't exactly the best thing to step up and then subsequently step down the size of the tubing. It will hurt flow rates. You could try and get your hands on a DDC with a modded inlet. You'll get 140 gph and like 9.5' of head. Should cost less than 2 CSP Mags, and it validated as a reliable pump.

Unfortunatly the black ice i have is one of the older ones with permanent 1/2 fittings and would require a lot of work for such a small change. Although it seems like if that is more freeflowing than the rest would actually improve the flow compared to having it be 3/8 as well.

Twin MAGs would fit what I want to do the best, but I will be doing my homework before I decide for certain. These are about $50 each compared to 75 for the DDC, wouldnt be that much more for the mags really.

3/8" ID soft silicone tubing will go right over 1/2" stubs. Other tubing may work fine as well (try putting in hot water first to soften).
I've swapped a couple of systems from 3/8 to 1/2 ID tubing and saw no difference in MBM-reported die temps. I made a point of not dismounting/remounting the wb on one of the systems to make sure I wasn't confusing the issue with a slightly better/worse mount. Hadn't bothered to with the first system as it's a PITA to change hoses with the wb in place...

noise trivia: I've noticed that the 3/8 soft silicone does a better job of not transmitting pump vibrations than the 1/2 (both thickwall tubing).

I think I have decided on 3/8, due to not wanting a lot of overall bulk in the system, for my plan 1/2 would be a lot to deal with after I gutted my case so I could work on it. . Seems as long as you have enough pump to overcome the higher restriction it really doesnt matter performance wise, and blocks top out after a certain flow rate regardless.

The system I am planning out so far will be:
DD TDX with High FLow 3/8
DD Acetal low prof Maze 4 GPU with High Flow 3/8
2x CSP-MAG in parallel 3/8
DD BIX 1/2
Tygon 3606 3/8
2x custom round reservoirs with DD hi flow barbs

On the following gear:
Abit AV8
AMD Athlon 64 3000+ WInchester
2x256 GeIL Platinum DDR500 (dual channel)
Sapphire Radeon 9800 pro 128
2x Hitachi 160gb SATA
other drives etc

and this is the case I am working with here

I miss the thread where this was said to be a good idea? Didnt even know someone got a hold of the csp-mags yet, let alone it was a good idea to put them in parallel...

1/2" inlet modded DDC is more like.... 190Gph and 13' head @12v.

with user modifications?

edit: if he's sticking to 3/8" inner dia hose, why should he modify it?

7/16" ID Tygon is where it's at...

I'll second this one. I have 3/8" ID Primochill tubing (I liked the color) in my system which has two 1/2" components (mcw50 with barbs epoxied, and a BIP 3 with integrated 1/2" barbs). Sorry about the discreprancy with the performance of the modded DDC, I only suggested it as an alternative to what was not available (the two CSP Mags).

7/16" ID tygon over 1/2" barbs... yeah that probably would be the best. I haven't tried it but Cather swears by it. Too late to change Der Brewling?

Some of my gear hasnt been ordered just yet,obviously Im waiting on the mags but have begun to get the case ready with moutning the rad up front (kisses removable hdd rack goodbye) and the reses on top. Luckily my gf helped me decied on the placement of the tubes, and now they wont be nearly as much work as I was thinking.

I have the BIX and the TDX block with 3/8, still need tubing, some more DD fittings, the gpu block, and the pumps. I have the materials to build the res tanks however. My pocket book is ready and raring to get this stuff once I decide for sure what I am doing.

Where can I find 7/16 ID tygon?

And yea Ive heard of the putting it in hot water trick, never did try it though.

and np about the DDC, its good to know all options.

Ill try and get some kind of pictures up soon of my progress, probably in a project log somewhere else on the forums here. Im just going for something a little differant than most

http://www.usplastic.com/catalog/pro...ookie%5Ftest=1

Item ID: 54047

Ah nice find, has anyone here used this kind before?

As all but the BIX is 3/8 i think 3/8 tygon will work just fine. 7/16 is a good compramise in between though, I will think about it some more.

Thier 3606 is cheaper than others for 3/8 with 3/32 wall, they only carry 7/16 with 1/16 wall for that type though.

I'm using 7/17 tygon. The best thing about this is that I'm still getting the same results as when I was using 1/2" but now bending it is very easy and the hose does not give too much stress to the components (i.e. cpu & vga).

Yes, Cathar's main positive points about the 7/16" tubing was that it fit snugly over 1/2" OD fittings and was easier to bend and maneuver than 1/2" ID tubing.

I assume with hose clamps 7/16 does fine on 3/8 barbs as well. Is that type of Tygon (the link) what you guys are using?

yes... that link is where I actually got mine... BTW, I'm a bit pessimistic about using 7/16 on 3/8 barbs, although I don't know of anyone even trying it... let us know how it goes if you decide to go for 7/16 hose on 3/8 barbs.

At least this would settle the argument forever going half way in the middle :)

Cathar had stated that 7/16" worked fine on 3/8" barbs when clamped down tightly.

I have the 7/16" tubing and it fits easily over the 3/8"barbs without being sloppy.

So I expect it will clamp just fine.

You can also get 7/16" tubing from Mcmaster-Carr as well.