also should consider your PSU, will it enough to power up 9800GX2, it really Power-Hungry & need a 6-pin & a 8 pin power socket.
correct me if i'm wrong.

Corsair, PC Power & Cooling, ULtra X3,Antec, Silverstone & Cooler Master,etc are good PSU w/ 750w will be safe . Don't run your PSU at Peak load. but if you going for Quad SLI, then choose PSU more than 1000W.

PhysX is supported on all GeForce 8-series, 9-series and 200-series GPUs with a minimum of 256MB dedicated graphics memory. PhsyX software is include in Geforce 182.08 WHQL driver for GeForce 6, 7, 8, 9, and 200-series desktop GPUs

motherboard with nvidia chipset like 680i = pcie x16/pcie x16/pcie x8. 780i & 790 i =pcie 2 x16/pcie 2 x16/pcie x16

nVidia Geforce GTX 275 released:
The NVIDIA® GeForce® GTX 275 GPU with CUDA™ technology delivers astonishing gaming performance with dazzling PhysX gaming effects along with incredible GPU computing performance for everything from video transcoding to video and photo editing.


Sacred 2 image captured on NVIDIA GPU. Provided by Ascaron Entertainment GmbH. The Gaming Performance You Demand
Experience best-in-class graphics performance in the hottest games such as Warhammer 40,000: Dawn of War II and Far Cry 2. And with full GPU-acceleration for NVIDIA PhysX™ technology, GeForce GTX 275 will change your 3D gaming experience by bringing dynamic forces of nature and massively destructible environments to games such as Sacred 2 and Mirror’s Edge. With GeForce GTX 275, get the graphics plus physics performance that your games demand.

The Power of GPU Computing
The GeForce GTX 275 GPU with CUDA technology not only provides astonishing gaming performance, but it also delivers incredible GPU computing performance for everything from video transcoding to video and photo editing. Whether it’s transcoding HD videos in minutes to your portable video player using Badaboom Media Converter, upscaling standard definition movies to near HD quality with Arcsoft SimHD, or rapidly editing digital photos using Adobe CS4, the GeForce GTX 275 GPU does it all with outstanding performance.i

i Applications must support CUDA technology to deliver performance speedups.
2nd Generation NVIDIA Unified Architecture: Second generation architecture delivers 50% more gaming performance over the first generation through enhanced processor cores that provide incredible shading horsepower.
3-way SLI Technologyi: Industry leading 3-way NVIDIA® SLI® technology offers amazing performance scaling by implementing 3-way AFR (Alternate Frame Rendering) for the world’s premier gaming solution under Windows Vista® with solid, state-of-the-art drivers.
DirectX 10 Support: Microsoft® DirectX® 10 GPU with full Shader Model 4.0 support delivers unparalleled levels of graphics realism and film-quality effects for today’s hottest games.
CUDA Technologyii: NVIDIA® CUDA™ technology unlocks the power of the GPU’s processor cores to accelerate the most demanding system tasks - such as video transcoding - delivering up to 20x performance over traditional CPUs.
PCI Express 2.0 Support: Designed for the new PCI Express 2.0 bus architecture offering the highest data transfer speeds for the most bandwidth-hungry games and 3D applications, while maintaining backwards compatibility with existing PCI Express motherboards for the broadest support.
SLI Multi-Monitor support: Switch seamlessly between multi-display desktop mode and full screen 3D gaming with SLI. And enjoy full multi-GPU support for dual-display capable 3D games such as World in Conflict, Supreme Commander Forged Alliance, and Flight Simulator X.
GigaThread™ Technology: Massively multi-threaded architecture supports thousands of independent, simultaneous threads, providing extreme processing efficiency in advanced, next-generation shader programs.
Lumenex™ Engine: Delivers stunning image quality and floating point accuracy at ultra-fast frame rates.
16x Anti-aliasing Technology: Lightning fast, high-quality anti-aliasing at up to 16x sample rates obliterates jagged edges.
128-bit floating point High Dynamic-Range (HDR) Lighting: Twice the precision of prior generations for incredibly realistic lighting effects—now with support for anti-aliasing.
OpenGL 3.0 Optimization and Support: Provides top-notch compatibility and performance for OpenGL applications.
Dual Dual-link DVI Support: Able to drive the industry’s largest and highest resolution flat-panel displays up to 2560x1600 and with support for High-bandwidth Digital Content Protection (HDCP).iii
HDMI Outputiv: Support for HDMI output enables sending both high-definition video and audio signals to an HDTV via a single cable.
PureVideo® HD Technologyv: The combination of high-definition video decode acceleration and post-processing that delivers unprecedented picture clarity, smooth video, accurate color, and precise image scaling for movies and video.
Discrete, Programmable Video Processor: NVIDIA PureVideo is a discrete programmable processing core in NVIDIA GPUs that provides superb picture quality and ultra-smooth movies with 100% offload of H.264 video decoding from the CPU and significantly reduced power consumption.
Dual-stream Hardware Acceleration: Supports picture-in-picture content for the ultimate interactive Blu-ray movie experience.
Dynamic Contrast Enhancement and Color Stretch: Dynamically provides post-processing and optimization of High Definition movies for spectacular picture clarity.
i NVIDIA SLI certified versions of GeForce PCI Express GPUs only. A GeForce GTX 275 GPU must be paired with another GeForce GTX 275 GPU (graphics card manufacturer can be different). SLI requires sufficient system cooling and a compatible power supply. Visit www.slizone.com for more information and a listing of SLI-Certified components.
ii Requires application support for CUDA technology.
iii Playback of HDCP protected content requires other HDCP-compatible components
iv Requires DVI-to-HDMI dongle and SPDIF audio cable from motherboard to graphics card
v Feature requires supported video software. Features may vary by product.
Main | FeaturesNote: The below specifications represent this GPU as incorporated into NVIDIA's reference graphics card design. Graphics card specifications may vary by Add-in-card manufacturer. Please refer to the Add-in-card manufacturers' website for actual shipping specifications.

GPU Engine Specs:
Processor Cores 240
Graphics Clock (MHz) 633 MHz
Processor Clock (MHz) 1404 MHz
Texture Fill Rate (billion/sec) 50.6

Memory Specs:
Memory Clock (MHz) 1134 MHz
Standard Memory Config 896 MB GDDR3
Memory Interface Width 448-bit
Memory Bandwidth (GB/sec) 127.0

Feature Support:
NVIDIA SLI®-ready* 2-way/3-Way
GeForce 3D Vision Ready
NVIDIA PureVideo® Technology* HD
NVIDIA PhysX™-ready *
NVIDIA CUDA™ Technology
Microsoft DirectX 10
OpenGL 3.0
Bus Support PCI-E 2.0
Certified for Windows Vista

view here:http://www.nvidia.com/object/product_geforce_gtx_275_us.html

This post has been edited by Ozone64: Apr 2 2009, 08:09 PM

Can use Rivatuner for manualy adjusting fan speed at different temperature. i can put up the link later.

now using two gtx275 SLI'ed, 3dmark vantage score just over P16322 only, processor OC'ed to 3.4ghz, & GPUs OC'ed at 743/1605/1281( clock/shader/memory), is it limited either by processor, ram or 22" monitor ?