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Overclocking the NVIDIA GeForce Video Card E-mail
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Written by Olin Coles   
Saturday, 06 September 2008
Table of Contents: Page Index
Overclocking the NVIDIA GeForce Video Card
Planning the Project
ATITool Overclocking
RivaTuner Overclocking
OC Performance Results
Building a custom BIOS
Programming the BIOS

OC Performance Results

I'm sure that people often wonder what kind of difference overclocking can have on a video card, which is exactly why I've put these charts together. Obviously every product is different and each model will produce its own unique results, but this should confirm the obvious: overclocking gives you more performance for free!

Stepan Hrbek is the mastermind behind Lightmark 2007, a program that allows you to benchmark real-time global illumination. Typical workloads in real-time rendering will shift, and Lightsmark simulates it. Global Illumination renders often take hours, so before Lightsmark real-time global illumination was limited to small scenes, small resolutions, low speeds, and specially crafted scenes with handmade optimizations. Lightsmark breaks all limits at once, running in reasonably sized scene (220000 triangles) in high resolutions at excellent speed. Lightsmark is comparable to lower-demand OpenGL video games, such as: Prey, Quake 4, and Doom 3.

This scene places medium-high demands on a graphics card processor and tests the maximum speed with which the scene can be properly displayed at each resolution. At the 1920x1200 resolution tested, the reference NVIDIA GeForce GTX 280 video card produced a 455 FPS for the scene, which the ZOTAC GeForce GTX 280 AMP! Edition rendered at 510 FPS. After an hour of trail-and-error overclocking, that same ZOTAC graphics card was pushed to produce 521 FPS. This results in a 15% improvement over stock, and 2% increase over the factory overclock.


Call of Duty 4: Modern Warfare runs on a proprietary game engine that Infinity Ward based off of the tried-and-true Q3 structure. This engine offers features such as true world-dynamic lighting, HDR lighting effects, dynamic shadows and depth of field. "Bullet Penetration" is calculated by the Infinity Ward COD4 game engine, taking into account things such as surface type and entity thickness. Certain objects, such as cars, and some buildings are destructible. This makes distinguishing cover from concealment important, as the meager protection provided by things such as wooden fences and thin walls does not fully shield players from harm as it does in many other games released during the same time period. Bullet speed and stopping power are decreased after penetrating an object, and this decrease is calculated realistically depending on the thickness and surface of the object penetrated.

This version of the game also makes use of a dynamic physics engine, a feature which was not implemented in previous Call of Duty titles for Windows PC's. The new in-game death animations are a combination of pre-set static animations combined with ragdoll physics. Infinity Ward's use of the well-debugged Quake 3 engine along with new dynamic physics implementation allows Call of Duty 4 to be playable by a wide range of computer hardware systems. The performance may be scaled for low-end graphic cards up to 4x Anti-Aliasing and 16x Tri-linear anisotropic texture filtering.

The coup d'etat scene when Al Asad takes over control offers medium-high stress on the video card. At 1920x1200 the reference NVIDIA GeForce GTX 280 video card produced a 92 FPS for this intro scene, which the ZOTAC AMP! Edition rendered at 98 FPS. Once I further-overclocked the ZOTAC graphics card, my performance improvements produced 104 FPS. This equals a 13% improvement over stock reference, and 6% / 6 FPS increase over the factory overclock.


Crysis uses a new graphics engine: the CryENGINE2, which is the successor to Far Cry's CryENGINE. CryENGINE2 is among the first engines to use the Direct3D 10 (DirectX10) framework of Windows Vista, but can also run using DirectX9, both on Vista and Windows XP. Roy Taylor, Vice President of Content Relations at NVIDIA, has spoken on the subject of the engine's complexity, stating that Crysis has over a million lines of code, 1GB of texture data, and 85,000 shaders. To get the most out of modern multicore processor architectures, CPU intensive subsystems of CryENGINE 2 such as physics, networking and sound, have been re-written to support multi-threading.

Benchmark Reviews uses the Crysis Benchmark Tool by Mad Boris to test frame rates in batches, which allows the results of many tests to be averaged. At 1920x1200 with no post-processing AA enabled, the reference NVIDIA GeForce GTX 280 was able to produce 43.9 FPS after three test loops. Given a healthy overclock at the factory, ZOTAC's GTX 280 AMP! Edition gave a 48.3 FPS but later pushed performance up to 49.8 FPS after an additional overclock. Crysis places the most stress possible from any currently available video game, and our overclocked GTX 280 produced a 13% improvement over stock and 3% over ZOTAC's factory overclocked performance.


So what does it all mean? Without getting into a complex answer, this data means that overclocking can yield a very notable improvement in video game performance. I tool an already maxed-out ZOTAC GeForce GTX 280 AMP! Edition video card, and pushed it ever farther. But could the same thing be done with a stock GeForce GTX 280? No, probably not to the same degree. NVIDIA has adopted a technique called "binning" where the best GPU's are sorted apart at their Taiwan Semiconductor Manufacturing Company (TSMC) fabrication plant. The very best graphics processors are then later resold to NVIDIA's add-in card partners (AIC's) who build their factory overclocked products with them.

Regardless, overclocking your video card clearly offers a benefit to the video frame rates in every game we tested. So now that you're armed with this information, would you make the changes permanent? In the next section, I outline the steps necessary to flash your video card BIOS with settings I've tested to be absolutely stable.



# Eng DirectorDenis Scott 2010-06-22 13:26
Please send your free Overclocking NVidia 6800XT Video Card.

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