To determine how much power
multi-core processors draw, PCSTATS will be measuring total power consumption
what the CPU is in idle and several CPU-stressed states.
To get an
accurate measurement, it's necessary to disable AMD and Intel's power saving and
CPU clock speed throttling technologies like Cool 'n' Quiet, EIST (speedstep)
and C1E power states.
To
simulate single-core load a program called Stress Prime (SP2004) is used. PCSTATS
set about stressing each processor from one to all cores. This programs gives
better insight into different power draw scenarios. The SP2004 program is
multi-threaded, allowing individual CPU cores to be stressed by each instance of
the program. Total system power consumption was read with the Extech Power
Analyzer Datalogger (model 380803). The Extech Power Analyzer is located between
the main 120AC supply and the PC's power supply.
Given
that motherboards vary across these test systems this is not a "true" measure of
CPU power draw alone, but rather a measurement of the total computer system
power draw, which we can compare for each specific platforms between the CPU
idle and CPU stressed states.
Does a two-chip motherboard
and a 95W TDP processor make a real difference?
The Core i5 750 processor is one of Intel's most
power-efficient mainstream offerings, and thanks to some intelligent power
management, it should be able to reach some very low power consumption
numbers...
| Total System Idle Power
Draw |
| Processor |
Total
System Power Draw |
| Intel Pentium 4 540 |
   150 Watts |
| Intel Pentium D 840 |
165 Watts |
| Intel Pentium D 940 |
168 Watts |
| Intel Core 2 Duo E6600 |
117 Watts |
| Intel Core 2 Duo E6750 |
123 Watts |
| Intel Core 2 Duo E8400 |
131 Watts |
 Intel Core i5 750 |
   124 Watts
|
| Intel Core i7 920 |
144 Watts |
| AMD Sempron 3600+ |
   120 Watts |
| AMD Athlon64 4000+ |
163 Watts |
| AMD Athlon64 FX-60 |
127 Watts |
| AMD Athlon64 X2 4800+ |
143 Watts |
| AMD Athlon64 X2 5000+ |
156 Watts |
| AMD Athlon64 FX-62 |
168 Watts |
| AMD Athlon II X2 250 |
128 Watts |
| AMD Athlon II X4 620 |
130 Watts |
| AMD Phenom II X3 720 |
155 Watts |
| AMD Phenom II X4 955 |
148 Watts |
| AMD Phenom
II X4 965 |
154 Watts |
At idle, the Core i5 750 system draws about as much
power as Intel's Core 2 Duo systems, which have only half the cores. The Core i5
750 is significantly more power efficient than its closest rivals, AMD's Phenom
II X4 processors.
| Total System Stressed
Power Draw - All Cores/Threads |
| Processor |
Total
System Power Draw (All Cores) |
| Intel Pentium 4 540 |
223 Watts |
| Intel Pentium D 840 (2 Core ) |
240 Watts |
| Intel Pentium D 940 (2 Core Load) |
253 Watts |
| Intel Core 2 Duo E6600 (2 Core Load) |
156 Watts |
| Intel Core 2 Duo E6750 (2 Core Load) |
163 Watts |
| Intel Core 2 Duo E8400 (2 Core Load) |
158 Watts |
| Intel Core i5 750 (1 Core Load) |
135 Watts
|
| Intel Core i5 750 (2
Core Load) |
146 Watts
|
| Intel Core i5 750 (3
Core Load) |
157 Watts
|
| Intel Core i5 750 (4
Core Load) |
169 Watts
|
| Intel Core i7 920 (8 Thread Load) |
213 Watts |
| AMD Sempron 3600+ |
148 Watts |
| AMD Athlon64 4000+ |
172 Watts |
| AMD Athlon64 FX-60 (2 Core Load) |
196 Watts |
| AMD Athlon64 X2 4800+ (2 Core Load) |
173 Watts |
| AMD Athlon64 X2 5000+ (2 Core Load) |
207 Watts |
| AMD Athlon64 FX-62 (2 Core Load) |
235 Watts |
| AMD Athlon II X2 250 (2 Core Load) |
163 Watts |
| AMD Athlon II X4 620 (4 Core Load) |
195 Watts |
| AMD Phenom
II X3 720 (3 Core Load) |
213 Watts |
| AMD Phenom II X4 955 (4 Core Load) |
236 Watts |
| AMD Phenom II X4 965 (4 Core Load) |
264 Watts |
Under load it's easy to see just how good a job of
taming this four-core mainstream processor. The Core i5 750 system is just shy
of a 170W draw when all four of its cores are under load. This is 40W less than
the Intel Core i7 920 system, and nearly 100W less than the AMD's Phenom II X4
965 processor!
Overclocking is up next, just how far can PCSTATS take a
quad-core that has just a 95W TDP?
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