Cooling X10SDV (Xeon D-1540/1541)

This all began with the purchase of an X10SDV-TLN4F-O for Gaussian09 and MOLPRO calculations (using tmpfs, so IO should not be limiting). When running calculations on all 8 cores I noticed that the cores were rarely above 2100 MHz and the temperatures were in the 60 - 75 °C. For comparison, my two X99 systems with Core i7 5960X processors having water cooling rarely get above 47 °C and alway ran at maximum turbo speed of 3500 MHz.

Time for a couple related notes. I changed the governor to performance using cpufreq and intel_pstate. Disabling pstate was not helpful because the BIOS does not deal properly with turbo (so far as I can tell) because the maximum speed was 2100 MHz when I tried that. This led me to believe thermal throttling was causing the issues.

What to do about the temperatures? Would changing the heatsink compound be enough? Should I just change the fan? Do I need a complete HSF overhaul? Finally, how would I test and assess performance of different solutions? The short answers were I wanted to try everything and HPCC is a decent stand in for Gaussian09 and MOLPRO because it has DGEMM and Linpack sections pretty much represent the computations in those programs (and previous testing with AMD systems showed it produced similar temperatures). HPCC with N = 24000 provided 25 minutes of run time (most of that being in the linpack section). Ambient temperatures fluctuated 1 - 2 °C, and were measured using a calibrated thermistor accurate to better than 0.1 °C. The CPU temperatures were measured using the built-in temperature sensor, and all reported temperatures are differentials. A bash script recorded the CPU temperatures every minute.

As for the heatsink, Alpha Nova Tech produced some custom 70 mm x 70 mm x 40 mm aluminum heatsinks having the same footprint as the stock heatsink (so I could reuse the screws and springs). Next up came the fan ducts, which I designed using OnShape. The two basic geometries involve one fan blowing down or a push-pull arrangement (at 50 ° from horizontal). These were printed using HIPS on a Lulzbot Mini.

Enough details, now on to the results.

HSF	Max	Avg
Stock	42	38
Stock-AS5	39	37
60 mm Everflow	23	20
60 mm Fractal	32	31
60 mm Panaflo	28	25
60 mm San Ace	30	28
60 mm YS Tech	28	25
60 mm Everflow	24	22
60 mm Fractal	32	31
60 mm San Ace	56	53
60 mm YS Tech	55	53
80 mm Akasa	29	27
80 mm Noctua	32	30
80 mm Sunon	23	21
80 mm Vantec	32	30
80 mm Sunon	24	22
92 mm Everflow	28	26
92 mm Gelid	30	27
92 mm Noctua	31	29
PP 60mm Everflow/San Ace	21	19
PP 60 mm Fractal/Noctua	29	26
PP 60 mm Noctua/Fractal	37	35
PP 60 mm Noctua/San Ace	30	27
PP 60 mm San Ace/Everflow	23	21
PP 60 mm San Ace/Fractal	27	26
PP 60 mm San Ace/Noctua	27	25
PP 70 mm Everflow15/Everflow15	23	20
PP 70 mm Everflow15/Everflow25	23	21
PP 70 mm Everflow25/Everlfow15	23	21
PP 70 mm Everflow25/Everflow25	23	21

Ok, so that tells us a couple things. The heatsink compound does reduce the temperature by a few degrees. The custom heatsink lowers the temperatures by approximately 10 °C, and the fan choice provides another 10 °C drop.

High static pressure fans reduce the temperature more than high flow rate fans (no real surprise here). Hence, the 60 mm San Ace and YS Tech, 80 mm Sunon, and 92 mm Everflow are the winners for single fan setups. The push-pull setup definitely lowers the temperatures drastically, especially the maxima. The Everflow 25 mm fans having the lowest noise output.

The losers were the Noctua and Gelid fans, though these were also the lowest noise models.

During all of the tests the processor frequency (as monitored by cat /proc/cpuinfo | grep MHz remained near 2600 MHz. Returning to the Gaussian09 and MOLPRO calculations still showed throttling, though not as bad as before (on average the frequencies remain around 2400 MHz). Hmmmmm...perhaps it is not thermal throttling after all, but at least I feel much better about running these X10SDV units full throttle.