Power Consumption / Temperature Testing
System Power Consumption
Our power consumption numbers are broken down into two categories: one which simply stresses all of the CPU cores with WPrime and another which puts a high amount of load on both the CPU cores and the IGP. The latter will only be included if a given processor includes a dedicated internal graphics sub-processor.
For the CPU power consumption test, we use the standard testing system (with an NVIDIA GTX 670 installed) and wait until the system and discrete GPU are at idle speeds in order to log the idle power consumption. After this, WPrime 1024M is looped for 15 minutes while the power consumption is logged with a calibrated power meter to determine the peak watts.
Please note that after extensive testing, we have found that simply plugging in a power meter to a wall outlet or UPS will NOT give you accurate power consumption numbers due to slight changes in the input voltage. Thus we use a Tripp-Lite 1800W line conditioner between the 120V outlet and the power meter.
While the i7-4960X has the same 130W TDP as the outgoing i7-3960X, the 22nm manufacturing process significantly reduces power consumption regardless of the processorís load.
In our testing, we noticed an approximate 30W drop at full load and nearly identical efficiency ratios at idle. This allows IVB-E to boast an excellent performance per watt ratio in many tasks, though Hawell processors do have it beat in some instances. It does seem like the 22nm technology is working exactly how Intel intended it to.
In order to test temperatures, we set all processors on a loop of Prime95ís Blend Test for 25 minutes and logged the peak temperature core over that period of time using Intelís XTU 4.2 utility. Ambient temperatures were kept at a constant 24įC. For cooling, a Noctua NH-U14S with two 140mm fans was used.
One of the major concerns with Intelís 22nm 3D technology is its heat output due to stacked transistors focusing their energy into one condensed area. Many are experiencing this with Haswell, which tends to pump a ridiculous amount of heat into a small area, causing fits for heatsinks and water cooling systems alike.
Due to some changes in its IHS design, Ivy Bridge-E effectively spreads the heat from its 1.86 billion transistors over a larger area, allowing it to be dissipated faster. As a result, our i7-4960X sample posted some relatively low temperature results at idle and full load. It was even able to beat out the i7-3960X in this respect, which certainly wasnít something we expected.
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