The biggest problem we’ve encountered when using high-end graphics solutions is that at the highest resolutions and settings, the cards cannot get data fast enough from the CPU and RAM to keep their graphics cores busy. In an effort to reduce this so-called “CPU bottleneck,” we overclocked our Core i7 processor to 4.00 GHz at a 200 MHz base clock.
|Test System Configuration|
|CPU||Intel Core i7 920 (2.66 GHz, 8.0 MB Cache)|
|Overclocked to 4.00 GHz (BCLK 200)|
|CPU Cooler||Swiftech Liquid Cooling: Apogee GTZ water block,|
|MCP-655b pump, and 3x120mm radiator|
|Intel X58/ICH10R Chipset, LGA-1366|
|RAM||6.0 GB Crucial DDR3-1600 Triple-Channel Kit|
|Overclocked to CAS 8-8-8-16|
|GTX 295 Graphics||2x GeForce GTX 295|
|2x 576 MHz GPU, GDDR3-1998|
|GTX 280 Graphics||3x EVGA GeForce GTX 280 PN: 01G-P3-1280-AR|
|602 MHz GPU, GDDR3-2214|
|Radeon HD 4870 X2 Graphics||2x Sapphire HD 4870 X2 PN: 100251SR|
|2x 750 MHz GPU, GDDR5-3600|
|Hard Drives||Seagate Barracuda ST3500641AS|
|0.5 TB, 7,200 RPM, 16 MB Cache|
|Sound||Integrated HD Audio|
|Network||Integrated Gigabit Networking|
|Power||Cooler Master RS-850-EMBA|
|ATX12V v2.2. EPS12V, 850W, 64A combined +12V|
|Optical||LG GGC-H20LK 6X Blu-ray/HD DVD-ROM, 16X DVD±R|
|OS||Microsoft Windows Vista Ultimate x64 SP1|
|Graphics||NVidia Forceware 181.20 Beta|
|ATI 8.561.3.0000 Beta|
|Chipset||Intel INF 188.8.131.526|
Cooling an overclocked Core i7 CPU isn’t a task for lightweights, so we added Swiftech’s latest Apogee GTZ water block to the liquid-cooling kit we normally use for motherboard testing.
Feeding data quickly to the CPU are three 2.0 GB DDR3-1600 modules from Crucial. These particular samples are part of an upcoming High-End Triple-Channel shootout; watch for it in a few days.
Including 3-way SLI tests required a motherboard with proper slot spacing. Gigabyte’s EX58-Extreme worked well on our open platform, though the third card does extend below the lowest slot on standard cases.
Our second card came from MSI; its N295GTX-M201792 arrived overclocked to 655MHz GPU with GDDR3-2100 memory. We actually had to underclock this card to 576MHz/GDDR3-2000 reference speeds to make it cooperate with our reference card in Quad SLI. MSI says it could be releasing an overclocked board soon, which we'll be anxiously awaiting.
Our GTX-295 graphics cards were set to reference clock speeds, so it made sense to use reference-speed HD 4870 X2s in an apples-to-apples comparison. Our cards came from Sapphire.
Finally, the GTX 280 sets the standard for judging GTX 295 performance improvements. We tested three reference-speed cards in single, SLI, and 3-way SLI.
|Call of Duty: World at War||Patch 1.1, FRAPS/saved game Highest Quality Settings, No AA / No AF, vsync off Highest Quality Settings, 4x AA / Max AF, vsync off|
|Crysis||Patch 1.2.1, DirectX 10, 64-bit executable, benchmark tool Very High Quality Settings, No AA / No AF (Forced) Very High Quality Settings, 4x AA / 8x AF (Forced)|
|Far Cry 2||DirectX 10, Steam Version, in-game benchmark Very High Quality Settings, No AA, No AF (Forced) Very High Quality Settings, 4x AA, 8x AF (Forced)|
|Left 4 Dead||Very High Details, No AA / No AF, vsync off Very High Details, 4xAA / 8x AF, vysnc off|
|World in Conflict||Patch 1009, DirectX 10, timedemo Very High Quality Settings, No AA / No AF, vsync off Very High Quality Settings, 4x AA / 16x AF, vsync off|
|3D Mark Vantage||Version 1.02: 3DMARK, GPU, CPU scores Performance, High, Extreme Presets|