|Intel Core i5-661 Processor BX80616I5661|
|Reviews - Featured Reviews: Processors|
|Written by David Ramsey|
|Tuesday, 16 February 2010|
Page 9 of 10
Life is not as affordable as it used to be, and items such as gasoline, natural gas, and electricity all top the list of resources which have exploded in price over the past few years. The Intel Core i5-661 BX80616I5661 with its integrated video has the highest maximum power consumption of any of the new Clarkdale processors, at 87 watts while the other processors in the family max out at 73 watts; possibly this is due to the higher standard speed of 900MHz on the iGPU; other processors in the Clarkdale lineup run their iGPUs at 700MHz. However, even in the case of the i5-661, its iGPU will likely draw much less power than even the lowest-end graphics card.
To measure system power consumption, Benchmark Reviews uses the Kill-A-Watt EZ (model P4460) power meter made by P3 International. A baseline test is taken as the system is allowed to boot into Windows and rest idle at the login screen for three minutes before power consumption is recorded. Once the baseline reading has been taken, Lavalys EVEREST Ultimate Edition is loaded and the System Stability Test is run with 100% stress on the CPU and FPU for five minutes; to simultaneously stress the iGPU, I ran a simultaneous instance of Furmark.
The purpose of this test is to show the difference in power consumption between idle and loaded processor states. At the standard clock speed, I ran the tests with the SpeedStep, C1E, and C-State Tech features enabled (for maximum efficiency); they were disabled for the overclocking tests. Note that these numbers represent the power draw of the entire test system, and not just the processor.
As you can see, the Core i5-661's impressive overclocking abilities come with equally impressive increases in power consumption; required power virtually doubled with the overclock, although CPU performance only increased about 30%, so performance per watt dropped significantly. Temperatures rose dramatically, too: with the third-party cooler used in these tests and an ambient temperature of 26 degrees Centigrade, CPU temperature under load was 36 degrees Centigrade with the stock clock, power saving on, and 77 degrees Centigrade overclocked, power saving off. That these temperatures were recorded on an open-air test bed with a large third party cooler means that this overclock would not be possible with the stock Intel cooler in a small HTPC case.