Component cooling priority. CPU vs GPU

[joshreddevil]

I have a Nzxt Kraken X61 currently cooling the CPU (i54690k oc'd) and a GTX 970. I was thinking since there's room I'd add a second cooler (120/140mm) with a G10 adapter to the GPU the question is which rad would be better for which component. The GPU tends to run hotter so I'd assume that attaching the 280mm rad to it would be the most sensible. Has anyone done this and knows what works best?

 

[JofaMang]

Because of their heat signature (larger area for heat produced) liquid cooling for GPU is far more effective for the dollars invested. If you want to OC the GPU, a CLC with the G10 adapter will be a strong part of the process.

Not to mention, your CPU, non-OC, will be less likely of a bottleneck compared to your GPU, so extracting more performance from your GPU may give you a bigger realworld gain than OCing your CPU.

 

[Vellinious]

Even a small rad with water cooling on a GPU is sufficient. You'll want the bigger radiator on the CPU, as even under water and overclocked, they can reach their thermal threshold quite easily. The 970s are relatively limited in overclocking potential because they're locked at the VRM to not allow more than 1.3v, and that's only with a bios mod. With the stock bios, you'll be limited to 1.256v or less. Even with a single 120 on the GPU, you'll be hard pressed to push it to 50c+ on the stock bios, even with pretty high ambient room temps.

Bigger rad on CPU
Smaller rad on GPU

= )

 

[rubix_1011]

GPU typically is going to be higher TDP, even double a CPU in many instances.

GPU does have a higher thermal threshold, so having a poor cooling delta on a GPU isn't as detrimental as a poor cooling delta on a CPU.

 

[Vellinious]

^^This

 

[ohenryy]

Nowadays CPU's heat output is half or less what a normal (not even talking about Titan X) GPUs.
That might change with the new gen of gpu's on 16nm, but dont think so, with each having 8billion transistors will be hard to have them less than 150w.

 

[rubix_1011]

Bloomfield - 731 million transistors - 130w TDP
Haswell - 1.4 billion transistors - 88w TDP

A Titan X (8 billion transistors) and a GTX 480 (3 billion transistors) both have a 250w TDP.

Just having an increase of transistors does not necessarily equate to an increase in TDP.

 

[JofaMang]

Specific heat intensity is also part of the equation. GPUs heat is spread fairly evenly across their entire chip. CPUs tend to have more pointed locations that produce the heat, which would inflate a required amount of cooling to maintain, vs a more evenly distributed heat source. The density of the heat is very very relevant to how easy it is to cool, and since GPUs are far less dense, there would be a greater benefit to cooling a GPU vs a CPU with the exact same part.

The G10 bracket proves this. Mediocre CPU coolers do wonders on GPUs using this bracket.

 

[Vellinious]

Look...this is really easy to understand.

Overclock a GPU under water, especially a 970, and without SERIOUS hardware mods to crank the voltage up to insanely high levels, where extreme cooling should be used anyway, you're NEVER going to push it hard enough to really need a lot of radiator to keep it happy.

Overclock a CPU under water, ANY CPU, and with just very mild modifications in the bios to increase voltage, you can easily get the thermal limits of the CPU. So, keeping them cooler, is more important.

CPU = big rad
GPU = small rad

This is SIMPLE loop design stuff.....