The impact of tubing sizes

[Top Nurse]

Nah. 3/8" isn't bad but any lower and you'll start seeing marked changes in temps. Like Cathar pointed out, the difference between 1/2" to 3/8" isn't that bad and sees 3/8" as the sweet spot.

Just choose between either 1/2", 7/16" or 3/8" to do whatever suits your needs best.

Perhaps you might want to re-read the first post and take a gander at the pretty pics. Actually he sees the sweet spot at 5/16" (8mm) ID because the 5/16" with a push-fit has essentially the same graph as a 3/8" with a hose barb. And in actuality the difference between the worst and the best is only a measly 1.11 C. I don't think a 1.11 C difference is going to change much in the real world.

For the various tubing/fitting sizes, the PQ curves for a full system for each tubing type looks like this:



I overlaid the curves onto the PQ graph for the Laing DDC1+

Okay, the more astute of you will point out that the block C/W is really the case-to-block C/W, and that the actual CPU-die-to-block C/W is a lot higher. Even if we triple block the C/W (which would be an absolute upper limit based upon older research), we get:

6.35mm quick fit = 50.11C
8mm barbed = 49.74C
8mm quick fit = 49.31
9.6mm barbed = 49.25C
9.6mm quick fit = 49.04C
11.1mm barbed = 49.01C
12.7mm barbed = 49.00C

I'll leave it to everyone's own personal value based judgement to determine the relative importance of the differences seen....

It's certainly not the 5C figure that people bandy about. I never expected that it ever would be myself. In my own testing with arbitrarily choking the flow-rate in a test-system, I've always been amazed at the low flow resilience of many setups. Below 2LPM is where things start getting pear shaped quickly for most systems. My recommendation is that even if you're a low-flow fanatic, always ensure that your flow-rates are above 2LPM at the very least, and preferably above 3LPM if at all possible. Still, even when given 1/4" tubing installed with quick-fits and a decent pump like a DDC2, we can see that flow-rates in excess of 4LPM aren't a problem.