| Plattform | |
|---|---|
| CPU I | Intel Core 2 Duo E6850
65 nm; 3000 MHz, 4 MB L2 Cache |
| CPU II | Intel Core 2 Extreme QX6850
65 nm; 3000 MHz, 8 MB L2 Cache |
| CPU III | Intel Pentium D 830
90 nm; 3000 MHz, 2 MB L2 Cache |
| CPU IV | Intel Pentium 4 630
90 nm; 3000 MHz, 2 MB L2 Cache |
| Motherboard I | Asus P5E3 Deluxe, Rev: 1.03
Chipset: Intel X38, BIOS 0402 (2007-09-19) |
| RAM | Crucial BL12864BA1608.8SFB
2x 1024 MB DDR3-1066 (CL 7-7-7-20 2T) |
| Hard Disk Drive | 1 Western Digital WD5000AAKS
500 GB, 7,200 RPM, 16 MB cache, SATA/300 |
| DVD-ROM | Samsung SH-S183 |
| Graphics Card | Gigabyte GV-RX385512H
GPU: Radeon HD 3850 (670 MHz) RAM: 512 MB GDDR3 (830 MHz) |
| Sound Card | Integrated |
| Power Supply | Coolermaster RS850-EMBA
ATX 12V 2.2, 850 W |
| System Software & Drivers | |
| OS | Windows XP Professional 5.10.2600, Service Pack 2 |
| DirectX Version | 9.0c (4.09.0000.0904) |
| Platform Drivers Intel | Version 8.3.1.1009 |
| Graphics Drivers ATI | Catalyst 7.11 |
Benchmarks and Settings
| Benchmarks and Settings | |
|---|---|
| Sysmark 2007 Preview | Version 1.02
Official Run |






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http://www.techarp.com/showarticle.aspx?artno=520
For a load that will use all processors, I believe that testing will show better performance per watt for a quad core compared to a dual (or even single) core because there is little or no additional overhead from the motherboard or powersupply or hard drives when adding an additional core.
It may be easier to understand this by comparing running 2 separate PCs with dual core CPUs in them vs. running a single PC with a quad core CPU. The quad core system won't need another motherboard, power supply, fans, drives, etc. so all those items are areas of power savings.
From the published tests above, the 2 extra cores consume 195-132=63 watts at max load and 94-77=17 watts at idle. That is in contrast to adding a 2nd system identical to the E6850 testbox which used 132 watts at max and 77 at idle.
A simplistic scaling using a spreadsheet, and assuming that performance doubles going from dual to quad cores (reasonable for x264 encodes), shows that:
state cores watts perf/watt perf perf/core perf ratio
Idle 2 77 1.46 112.42 56.21 1
Idle 4 94 2.391914894 224.84 56.21 1.638
Avg 2 90 1.46 131.4 65.7 1
Avg 4 112 2.346428571 262.8 65.7 1.607
Max 2 132 1.46 192.72 96.36 1
Max 4 195 1.976615385 385.44 96.36 1.354
In other words, using the system power numbers given, the quad core can be 35% to 64% more efficient than using a dual core, if given an appropriate load. A look at the Sysmark benchmark scores will show you that it did not scale up very much going from dual to quad.