Phenom II X2 550 O/C Performance And Efficiency

by Thomas Soderstrom

AMD Phenom II X2 Test Settings
	Default Settings	Overclock Settings
CPU	AMD Phenom II X2 550 3.1 GHz 1MB L2+6MB L3 Cache, 1.288V	3.94 GHz (19.5x 202 MHz), 1.50V
RAM	DDR3-1333 CAS 9-9-9-24, 1.50V	DDR3-1616 CAS 6-6-5-18, 1.65V
Motherboard	MSI 790FX-GD70 Socket AM3, 790FX/SB750, BIOS 1.3 (04/27/2009)
Graphics	Zotac GeForce GTX260² 576MHz GPU, 999 MHz Shader, 896MB GDDR3-2484
Hard Drive	Western Digital VelociRaptor WD30000HLFS 300 MB, 10,000 RPM, 16 MB Cache
Sound	Integrated HD Audio
Networking	Integrated Gigabit LAN
Software
Operating System	Microsoft Windows Vista Ultimate x64 SP1
Graphics	GeForce 182.08 Desktop

A clock speed increase of 27% won’t surprise many experienced overclockers, but the Phenom II X2 550 started out at a fairly high 3.10 GHz. Its final clock rate of 3.94 GHz is fairly impressive for an AMD processor, even though the percent-gained is not. Does this increase translate directly into CPU performance?

CPU Arithmetic performance improved by 25%, while Multimedia extensions performance increased by 26%. The small difference between frequency improvement and performance improvement can likely be attributed to our use of a near-stock HT clock, as described on this guide’s previous page.

Our efforts to reduce memory timings using the processor’s highest memory ratio resulted in a tiny 8% gain in memory performance.

Average power consumption increased by 33%, mostly because of the increased CPU core voltage.

An average CPU performance increase of 26% at an average power increase of 33% yields an average efficiency decrease of around 5%. Overclockers looking for improved efficiency can instead choose a lower core voltage, as overclocking at stock voltage, though limited in performance gain, usually increases efficiency.