Building a new system. 3/8 vs 1/2 tubing size.

[96s10]

Im gathering parts together for my new system and wondering if 1/2 tubing is worth the gain? I mean it takes up more space and is harder to get tight bends with.

I'll be cooling my CPU & 2x video cards.

Thoughts?? :santa: :santa: :santa:

[RDWest2005]

From all i've read from the vets of wc-ing - faster the flow - the better performance

here is ya an example
I first got the thermaltake big water kit
dropped my temps 20 degrees
but with 1/4" tubing and burnin test - temps would climb around 16 degrees higher

now with BIX3 and 1/2" tubes - seems that bo matter what i do it won't climb but at most 5 degrees

and i have about a 30 degree drom from intel HSF now

~RD

[rogerdugans]

Bigger tubing means more cooling potential is available.
It doesn't always mean you will USE all of that potential. ;)

A well done 3/8" tube system can give about the same results in a system that is NOT running really maxed out, and the tubing is a bit easier to work with.

The larger tubing is more "forgiving" of poorly routed tubing though- less flow restriction to start with so if you do add restriction with tight bends, etcetera, it will not impact temps quite as much.

In general, I prefer to go with larger tube just to keep my options open, but I also do some fairly small LAN systems and use both 3/8" and even 1/4" tube in them.
Figure out where your priorities lie (max performance?) and how much room you have to work with.

[fuzzba11]

I just 'downgraded' from 1/2" to 3/8" and didn't notice any performance decrease, it really depends on the pump that you choose.

[calvin]

not much differance :shrug:

[Moto7451]

From all i've read from the vets of wc-ing - faster the flow - the better performance

here is ya an example
I first got the thermaltake big water kit
dropped my temps 20 degrees
but with 1/4" tubing and burnin test - temps would climb around 16 degrees higher

now with BIX3 and 1/2" tubes - seems that bo matter what i do it won't climb but at most 5 degrees

and i have about a 30 degree drom from intel HSF now

~RD

Thats not exactly a comparison of tubing. Using that BIX3 is what netted you that small temp delta. If you ran that system with all 1/4" the performance would be pretty similar if not the same. My system used to be half 1/4" & half 3/4" & when I finally switched to all 1/2" I didn't see any performance that wouldn't be attributed to the better water block I had also installed.

[Seven7Thirty30]

Make sure you get some cool wraps (anti-kink tubing wire) if you're going to go with 1/2 inch.

[clocker2]

Make sure you get some cool wraps (anti-kink tubing wire) if you're going to go with 1/2 inch.
What for?
Use Tygon and you're all set.

[citronym]

Yea coolsleeves are really only needed in special situations, and even then, there are other options. Often when something like that is needed, there is a better way to go.

[Maviryk]

Use 3/8" or even 7/16" tubing stretched over 1/2" barbs, this makes for the perfect performance and routing combination.

[Como]

im actualy in the same situation. my last system was 1/2", but im considering a new system with less room to work with. i cant decide, but heres my thought process...

1/2" is tried and proven, but so is 3/8.
3/8 is just 1/8 smaller than 1/4, not a huge difference.

experianced watercoolers will always say the water temp difference wont ever vary more than 1-2 C throughout the loop, meaning water coming out of the cpu and water going into the cpu generally arent that much different.

So, smaler tubing and LOWER flow would create a larger difference, but would also let the hotter water cool for longer in the rad.

as far as im concearned, in theory, it wont make much of a difference, so im probably going with 3/8.

btw, watercooling a rackmount in a self-contained not-obvious way is hard.

[speed bump]

compromise use 7/16" tubing over 1/2" barbs. Space like 3/8" tubing and flow very close to 1/2" tubing.

[Como]

compromise use 7/16" tubing over 1/2" barbs. Space like 3/8" tubing and flow very close to 1/2" tubing.

also a good point. 3/8" barbs will have a smaller ID than 3/8" tubes. 1/2" barbs would probably have the ID matched pretty well with some 7/16" tubing.

[Killaapp]

there ya go, 7/16 tubing is really the way to go.

[96s10]

Where would u get 7/16 tubing?? And how hard is this going to be?? I mean its gonna be super tight no??

But it sounds like a great idea!!! :santa2: :santa:

[Alchemy1]

http://www.mcmaster.com/

Part # 5233K43 or 5233K44. The second has a larger OD and thicker walls...which makes for better bends. If you have trouble getting the tubing on the barbs either dip the ends in boiling water or use a little water and dish detergent.

[outhouse]

i used 3/8 and for a short while i was in the top 10 overall 3dmark03 with a single bix then when sli came in i got knocked down for my rig using a cpu,northbridge, and gpu blocks. 3/8 was the way too get it all to fit. theres more to meet the eye then tubing size 1/2 barbs and the 7/16th would be the best if you dont have the room for 1/2 and if you do have a ton of bends then the 3/8 will work better then the 7/16

its up to you and your rig

[rogerdugans]

theres more to meet the eye then tubing size


That is really the truth of it.

Many of us have taken the "easy way out" over the years and just gone with "bigger is better" but situations, cases and other variables all add together and add up to this:

A well designed system will perform better than a badly designed one.

All things being equal- which is rare in the real world- larger tube WILL get you more cooling potential as long as it fits well in the system.

Smooth radius 3/8 tube is likely to do better than kinked 1/2 though. ;)

One way in which we are fortunate is that tubing is one of the least expensive components in water cooling. You can, with a bit of time and hassle and very little money, test both 3/8 and 1/2 in most systems and see what really works best for you. (I skipped the 7/16 size because it slots in between and can go both ways.)

[96s10]

One question guys, how hard would it be to get that thicker 7/16 i.d. / 5/8 o.d. to fit over the 1/2 fittings? I see its got a nice bend radius capability!

[Cathar]

One question guys, how hard would it be to get that thicker 7/16 i.d. / 5/8 o.d. to fit over the 1/2 fittings? I see its got a nice bend radius capability!

Very easy. Just push it on. The ID of the tubing is about the same as the lip of the 1/2" OD barbs. You just kind of push it on slightly side-ways, and it stretches over most 1/2" OD barbs with a small amount of effort. Creates a very tight snug fit, great for added leak protection. Some 1/2" ID tubings, especially Clearflex 60, tend to stretch over time on the barbs and can leak if not clamped on very tightly. Have had no such issues with the 7/16" ID stuff, even when unclamped and pushing up to 20PSI for a stress test.

It is a little harder to get the 7/16" ID tubing over the 14mm OD barbs of the D5 pumps (DangerDen D5, MCP655), but it will go over with a little bit of effort, and without resorting to heating the tubing up in hot water first. 5/8" OD barbs is about the absolute limit of how far 7/16" ID tubing will go.

[96s10]

Great, thank you very much for the info!! :D

[Otter]

So, smaler tubing and LOWER flow would create a larger difference, but would also let the hotter water cool for longer in the rad.
The only reason smaller tubing would give hotter water in the rad is if it reduced the cooling capacity of the system.

While it's true that a more restrictive loop will allow the water to remain in the rad longer on each trip, this is not advantagous. Though many people will tell you that water needs dwell time in the radiator, it's simply not true. As long as there is always warm water in the rad, the rad will have a source of heat to transfer to the air. Yes, the longer it takes the water to make the trip through the rad, the more it will cool off. But this does not increase the cooling capacity of the radiator. It decreases the cooling capacity because the temperature of the water at one end is significantly lower. Faster flow keeps the temp up at the far end of the rad, thus increasing the cooling capacity.

But the differences in radiator performance are not the main reason to design for better flow. Radiators tend to be limited more by air flow than water flow, hence better or worse flow doesn't make much difference. However, better flow makes a significant difference at the CPU block, and depending on what you're trying to do, that could be important.

[Otter]

There's a great discussion about 7/16" tubing here.
http://www.ocforums.com/showthread.php?t=331742

Cathar calculates that in short loops, it can actually perform better than 1/2". I'm not sure if anyone has actually tested this, but in the absence of tests, I'll take Cathar's calcualtions. He definitely knows about flow.