Thinner vs. thicker tubing.

[yoyoguy]

Right now the only things in my loop are my cpu block and a single 120 rad, I'm using 1/4" ID 3/8" OD tubing and it keeps it cool enough. I will be upgrading soon and I was wondering if I should use thicker tubing or keep my current tubing, and what the pros/cons would be for each.

It seems like thinner tubing would have a much higher flow rate but take less heat off the CPU. While thicker would have a slower flow rate but take more heat away. I was wondering if that is true and which one would be better suited to cool a system with:

AMD Phenom IIx4 3.3ghz (always changing the OC)
single 120 radiator
dual 120 radiator
Radeon 6950 (maybe crossfire in the future if the cards get cheap enough)

Open to suggestions on what to change/add as well.

[KaptCrunch]

3/8 id 1/2 od 1/16 wall to flimsy

3/8 id 5/8 od 1/8 wall OK

[lowfat]

Thinner tubing does not have more flow, it has less. However it really doesn't matter much. Anything over 3/8" has almost zero benefit. 1/4" has a slight decrease in flow but nothing substantial really. It is a lot easier to get 3/8" fittings though.

[Shadowmeph]

What ever you do don't buy any tubing with thin walls becasue what will happen is that the pump will suck it almost closed ( flatten it) that happened to me mind you the length I was using wasa good12 inches long

[lowfat]

I use thin wall tubing and have no problems with it. But I don't do super tight bends or anything.

[KaptCrunch]

Originally Posted by Shadowmeph

What ever you do don't buy any tubing with thin walls becasue what will happen is that the pump will suck it almost closed ( flatten it) that happened to me mind you the length I was using wasa good12 inches long

definitely will happen with awiki RD-30 suction closes thin tubing

LowFat probly doesn't have power using his auger pump

also thin wall goes to rubber when heated

[yoyoguy]

Thanks for the info guys. Really helps alot.

[AmuseMe]

Yup, I'm using 1/2 x 3/4 for my RD-30
I think your question has been answered

[Bao]

So to be clear (asked this elsewhere as well)

"Is there a reason to pick 3/8 ID - 5/8 OD tubing over (switching over to compression fittings) 3/8-1/2?

The cost difference isn't a lot but hey, money saved is money saved"

[clshades]

I personally like the 3/8 id - 1/2 od fittings myself. Tube isn't so big that it overwhelms the case but you'll need to watch the tight bends. These can be solved with various adapters and fittings. (part of the fun of water cooling) 3/8's is easy to work with and I think home depo sells the cheapo clear tubing you can use to layout a loop before using good stuff like Primochill.

You'll always be better off using 45* fittings instead of 90*'s but do what you must to make it work in your case. 1/2 fittings are more common in the buy/sell thread here which is how I've been building loops for several years now. I'm sure if you posted a "want to buy" thread for 3/8ID - 1/2OD compression fittings you'll find what you are looking for normally half price of new anyway.