Overclocking, Test System Configuration, And Benchmarks
The goal here was not to set any air-cooled overclocking records with our hardware samples, but rather to seek out stable clock speeds we could count on through the duration of the series, including these warm summer months. We therefore did not push voltages as high as you’d see in other articles. Load temperatures or diminishing returns from extra voltage were among reasons for dialing back a bit from the maximum stable overclock.
Those of you unfamiliar with overclocking AMD processors can check out these two “How To” guides for overclocking both "unlocked" Black Edition and standard "locked" AMD processors. Here, we used BIOS overclocking to first find the highest stable CPU core speed, and then tweak some additional performance by raising the northbridge (NB), HyperTransport (HT) link speed, and memory frequencies.
Apart from a tedious Phenom II X2 550 BE overclock, which went late into the night, the procedure was straightforward and uneventful. Despite 3+ hours of success in Prime 95’s “Blend” test, the only solution found for complete stability in Grand Theft Auto IV and Need for Speed Shift was to knock the Phenom II X2 550’s core speed down almost 80 MHz.
Readers should keep in mind that, by mixing locked and unlock processors in today’s story, there’s more to look at with each overclock than just the CPU core speed. For instance, while the Phenom II X6 1055T easily hit the highest core speed, less multiplier flexibility led to pairing with the lowest HT link speed and memory frequency.
BFG’s factory overclocks were used for both the GeForce GTX 260 and GTX 285. For other graphics cards, the GPU itself was dialed down about 20 MHz from its limit, while graphics memory was reduced by 20-30 MHz. The lone exception is the Radeon HD 5970, which didn’t get far without additional voltage. Once we added more juice, the card could no longer run Furmark without the VRM temperatures skyrocketing upward to the 120 degree throttling limit. This air-cooled design consideration prevented torture testing, so we chose to play it safe and run all Radeon HD 5970 numbers at the card’s stock speeds.
Be sure to check the test configuration table below for specifics on the overclocks achieved. For comparison purposes, we’ll include data for the overclocked Intel Core i7-920 from Part 3 of the series.
|Processors||AMD Phenom II X6 1055T (Thuban) 2.8 GHz, Socket AM3, 2000 MHz HT Link, 6 MB L3 cache. Overclocked to 3.864 GHz (14*276), 1.363 V, 2484 MHz NB, 1932 MHz HT Link|
|AMD Phenom II X4 955 Black Edition (Deneb) 3.2 GHz, Socket AM3, 2000 MHz HT Link, 6 MB L3 cache. Overclocked to 3.708 GHz (18*206), 1.45 V, 2472 MHz NB, 2060 MHz HT Link|
|AMD Phenom II X2 550 Black Edition (Callisto) 3.1 GHz, Socket AM3, 2000 MHz HT Link, 6 MB L3 cache. Overclocked to 3.774 GHz (18.5*204), 1.425 V, 2652 MHz NB, 2040 MHz HT Link|
|AMD Athlon II X4 640 (Propus) 3.0 GHz, Socket AM3, 2000 MHz HT Link, no L3 cache. Overclocked to 3.645 GHz (15*243), 1.45 V, 2430 MHz NB, 1944 MHz HT Link|
|Intel Core i7 920 (Bloomfield) 2.66 GHz, LGA 1366, 4.8 GT/s QPI, 8 MB Shared L3 cache, Overclocked to 4.0 GHz (21*190), 1.237 V idle, HTT Disabled|
|Motherboards||Asus Crosshair III Formula (Socket AM3) AMD 790FX /SB750, BIOS 1702 (5-26-10)|
|Asus Rampage II Extreme (LGA 1366) X58/ICH10, BIOS 1504 (07/23/09)|
|RAM||Corsair 4 GB (2 x 2 GB) DDR3-1600, 8-8-8-24 @ DDR3-1472 (X6 1055T), DDR3-1648 (X4 955 BE), DDR3-1632 (X2 550 BE), DDR3-1620 (X4 640), 1.65 V|
|Corsair 6 GB (3 x 2 GB) DDR3-1600, 8-8-8-24 @ DDR3-1524 (Core i7-920), 1.6 V|
|Graphics||ATI Radeon HD 5970 2 GB Stock @ 725 MHz GPU, 1000 MHz GDDR5|
|ATI Radeon HD 5870 1 GB OC @ 910 MHz GPU, 1270 MHz GDDR5|
|ATI Radeon HD 5750 1 GB OC @ 830 MHz GPU, 1320 MHz GDDR5|
|ATI Radeon HD 4890 1 GB OC @ 980 MHz Core, 1100 MHz GDDR5|
|Nvidia GeForce GTX 295 1792 MB OC @ 648 MHz Core, 1404 MHz Shaders, 1150 MHz GDDR3|
|Nvidia Geforce GTX 285 1 GB OC @ 712 MHz Core, 1620 MHz Shaders, 1332 MHz GDDR3|
|Nvidia Geforce GTX 260 896 MB OC @ 655 MHz GPU, 1404 MHz Shaders, 1125 MHz GDDR3|
|Hard Drives||Western Digital Caviar Black WD6401AALS, 640 GB, 7200 RPM, 32 MB Cache, SATA 3Gb/s|
|Power||Corsair CMPSU-850HX 850 W|
|CPU Coolers||Xigmatek HDT-S1283|
|Xigmatek Dark Knight-S1283V|
|Software and Drivers|
|Operating System||Microsoft Windows 7 Ultimate x64|
|Graphics Drivers||AMD Catalyst 9.12|
|Nvidia GeForce 195.62|
|Crysis||Patch 1.2.1, DirectX 10, 64-bit executable, benchmark tool, Very High Quality, No AA|
|Far Cry 2||Patch 1.03, DirectX 10, in-game benchmark, Ultra High Quality, 4x AA|
|S.T.A.L.K.E.R.: Clear Sky||Average of 4 segments 'a-tested object', DirectX 10/10.1, Ultra High Quality, EFD Lighting, no MSAA|
|Grand Theft Auto IV||Patch 184.108.40.206, in-game benchmark, High Quality Settings, High Textures, Medium View Distance|
|Fallout 3||Patch 1.7, Custom THG Benchmark "Capital Wasteland" (60 sec.), Ultra High Quality, 4x MSAA, 15x AF|
|Need For Speed Shift||Patch 1.02, Custom THG Benchmark "Dakota GP" (60 sec.), Highest Quality, 4x AA/ 16xAF|
|World in Conflict||Patch 1009, DirectX 10, timedemo, Very High Quality, 4x AA / 16x AF|