Well, the fun I'm having with the cooling system and testing, tweaking, testing to see what the limitations are and just how hot it will run or how cool it will run, for each component and how they interact.
Using:
* Prime95 for synthetic CPU loading (of different flavours and levels of torture)
* Furmark @3440x1440 for synthetic GPU stress loading
* MSI Afterburner for detailed metrics and graphs (stupid name, great program, previously known as RivaTuner until it was bought by MSI)
* MSI Afterburner for GPU clocks, voltage, limiters tuning.
* Argus Monitor for fan/pump control, more detailed metrics and graphs
* 3DMark "Time Spy" benchmark for short term performance 'scores' and comparisons with other peoples scores, not for competition, but as actual ... well benchmarks.
First with all fans and pumps at max, maximum noise, all vents, doors and grills open to the dust produced a performance benchmark score of 15,960. I soak tested the system with both prime95 and furmark and the GPU didn't get past 50*C, the CPU did get to 80*C (more on that later).
Then with all the doors, vents and filters back in place and a "sensible" quiet fan profile which is almost silent when not under load, but turns into the tornado again when it sees GPU and/or CPU load. That only dropped the benchmark score by 40 points. Heat soaking it showed only a few degrees increase and virtually no effect on peak clocks, though I didn't test/graph average clocks across cores. The "peak core clock" will be the "golden core" the rest will be less than that.
So, I tried to set up a "quiet gaming" profile. Again, pumps, fans all low or off until load is detected, but this time not immediately spinning up to full performance mode, but slowly following the temperature not reaching 100% until 80*C on the GPU. Similar profile for the CPU. The benchmark was still 15,9xx and the GPU didn't get past 61*C even under full stress load 61*C with a fan speed of 25% and it was stable. Wow. Maybe I went OTT on the cooling LOL, a bit.
So, why the hell not? I switched all the fans off and hit it in both the CPU and GPU with max load. After 5 minutes, the CPU was at 90*C, but still holding peak core clocks of 4.7Ghz! Damn psychopathic thing! However it was the GPU that was raising much more concern. It was slowly creeping up through 70*C. The GPU radiator had become too hot to hold my finger on. When would it stop? What temperature of water can the fittings, tubes and radiators handle (quick google, target under 40C, don't exceed 60C). Abort!
This test was so interesting because it forced me to try and derive the water temperature from the core temperatures. Alternating between 100% load and 0% load with no fan support produces a sloppy square wave on the thermals with an amplitude of, in my case about 30*C for the GPU and a huge 50*C on the CPU. Poking at the radiators with my mark one temp probe (my finger), it seemed fair that this amplitude more or less accounts for the thermal junction delta between the cores and the water (the main heat mass) in the loop and as it's circulating, the radiator.
So at 75*C which is where I chicken out, the water temp would only have been 45*C, too hot for me to stand in a shower that temp, so as it was uncomfortable under my finger after 10 seconds or so, I took 45*C as the finger in the air estimate. Which is fine.
I'm tempted to see how far I can actually push that, can I get the card to hit the thermal limiter before the water cooling system blows a radiator fitting out.
But first. I need a set of stick on thermal couples and a way to data log them on to the PC. (Sit down at the back Ardy folks!). Don't want to push it higher without an actual measured temp on the radiator and/or block itself.
Back to the CPU. 50*C is too high, and higher still if the CPU gets up to 95*C the water temp is still under 40C. I will have to remove the cooler, clean off the "came on it from the factory" thermal goo, add some "actually bought" stuff and see if that helps. I fear it won't help much. The issue is the heat spreader and multi die design. Unlike the GPU which is a dead flat block of silicon to interface with, the CPU has a tin lid on it which is thermally bonded to the dies underneath and tries to spread the heat out and prevent hot spotting. But it also introduces another thermal junction (or two) which do add up. De-lidded CPUs (when they were single die) would usually lower their junction loss to 40*C or less. I'm not going to start delidding it. As long as I can use the fans to keep the radiator under 35*C a 50*C delta I can live with.