- Aug 23, 2012
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- 10,510
I've got a 3.20 GHz i7 3930K (Sandy Bridge-E, 6 cores) and the RTS2011LC liquid cooler on an Intel DX79TO motherboard. Arctic Cooling MX-2 compound was used. I'm trying to calibrate my expectations for processor temperature vs. overclocking.
For this machine I'm doing highly parallel compiles of mixed C, C++, and Java code on a Ubuntu 12.04 system. So it's a situation where all cores are fully loaded up for about 30 minutes. The ambient temperature is about 21 or 22 degrees C. I'm kind of an overclocking noob so I'm just using the Overclocking Assistant in the BIOS.
When I set the Overclocking Assistant to the 1.0x profile, the CPU TSC is at 3.2 GHz and turbo mode goes up to 4GHz. RAM is at 1600MHz. Watching the output of 'turbostat' duribg the build, CPU speed remains consistently at 4GHz during the build, with core temperatures at about 65 degrees C.
With overclocking (1.25x profile), the CPU TSC is at 4Ghz and turbo mode goes up to 4.63GHz. The RAM is running at 2000MHz. In this scenario, when the build starts the CPU speed is at 4.63 GHz on all cores, but the processor cores heat up to about 75 degrees C, and soon I see a cyclical throttling of CPU frequency where it slows down, quickly cools off to ~60 degrees, and clocks back up again, in a repeated cycle. The system is stable but I'm losing performance.
I was wondering if anyone has had success in overclocking the 3930K without encountering what strongly appears to be periodic thermal throttling under sustained load, and if they had any advice. I'm thinking about perhaps adding a second fan to the other side of the heatsink for a push/pull setup.
For this machine I'm doing highly parallel compiles of mixed C, C++, and Java code on a Ubuntu 12.04 system. So it's a situation where all cores are fully loaded up for about 30 minutes. The ambient temperature is about 21 or 22 degrees C. I'm kind of an overclocking noob so I'm just using the Overclocking Assistant in the BIOS.
When I set the Overclocking Assistant to the 1.0x profile, the CPU TSC is at 3.2 GHz and turbo mode goes up to 4GHz. RAM is at 1600MHz. Watching the output of 'turbostat' duribg the build, CPU speed remains consistently at 4GHz during the build, with core temperatures at about 65 degrees C.
With overclocking (1.25x profile), the CPU TSC is at 4Ghz and turbo mode goes up to 4.63GHz. The RAM is running at 2000MHz. In this scenario, when the build starts the CPU speed is at 4.63 GHz on all cores, but the processor cores heat up to about 75 degrees C, and soon I see a cyclical throttling of CPU frequency where it slows down, quickly cools off to ~60 degrees, and clocks back up again, in a repeated cycle. The system is stable but I'm losing performance.
I was wondering if anyone has had success in overclocking the 3930K without encountering what strongly appears to be periodic thermal throttling under sustained load, and if they had any advice. I'm thinking about perhaps adding a second fan to the other side of the heatsink for a push/pull setup.
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