|Sapphire Radeon HD 4850 Video Card 100242L|
|Reviews - Featured Reviews: Video Cards|
|Written by Olin Coles|
|Thursday, 03 July 2008|
Page 8 of 13
Lightsmark Frame Rates
Stepan Hrbek is the mastermind behind Lightmark 2007, a program that allows you to benchmark real-time global illumination. Natural lighting makes artificial graphics life-like and real. Computers get faster, but rendering more polygons doesn't add value if lighting still looks faked, so insiders know that the next big thing is proper lighting; aka Realtime Global Illumination.
Typical workloads in real-time rendering will shift, and Lightsmark simulates it. Global Illumination renders often take hours, so is your computer fast enough for real-time?
Before Lightsmark, real-time global illumination was limited to small scenes, small resolutions, small speeds, 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: Call of Duty 4, Prey, Quake 4, and Doom 3.
At the ultra-low resolution of 1024x768, Lightsmark doesn't need to work very hard to get our graphic cards to render 786,432 pixel. This resolution forces each GPU to open up performance full-throttle and react to rapidly called tasks. Demands are quick-paced, and not surprisingly, a larger hardware communication overhead means that performance suffers. The extended memory address of the CrossFireX set and GeForce GTX 280 will be put to the test in this speed-critical benchmark.
Lighting is computed fully automatically in an original unmodified scene from 2007 game World of Padman. This benchmark is not tweaked for Lightsmark, and contains all sorts of geometrical difficulties with extra rooms hidden below the floor.
This scene places medium to low demands on a graphics card processor and tests the maximum speed with which the scene can be properly displayed at each resolution. At the lower resolution, the large frame buffer does not offer the same benefits as it would at a higher resolution. Additionally, the larger video memory means a longer round-trip for information, and when the resolution is low that trip doesn't last very long and needs to be completed very quickly.
This is our first evidence that matching the video card to the rest of your hardware is just as important as matching it to the expected task. Notice from this test that Lightsmark doesn't favor the goliath Gigabyte GeForce 9800 GX2, or the CrossFireX set of Radeon HD 4850 graphic cards. In fact, our GeForce 9800 GX2 was outperformed in every single Lightsmark test by GeForce 9800 GTX.
When we tested Crysis at 1650x1050, video frame buffer was not as critical as raw processing power. It helped, but obviously it didn't make a huge margin of difference. In Lightsmark, information is passed through the buffer and called on very quickly, and the only thing which was going to benefit this test was the appropriate ratio of graphical stream processors to video memory buffer, so that it could keep up with demands.
In terms of performance, this test offers very short but taxing graphics, and only the most nimble products with capable muscle can take advantage. This translates into trouble for anyone using new graphics hardware to render older (OpenGL) video games such as Doom 3 or Quake 4.
After all of the Lightsmark tests were complete, I'm sure these results aren't going to indicate anything in particular to most readers. As I mentioned before, the frame buffer has a whole lot to do with the speed of rendering. The larger the frame buffer, the longer it will take to complete the strobe of information. Lightsmark is meant to represent that collection of older games, which some of you might still be playing. Even Call of Duty 4: Modern Warfare runs on a proprietary game engine that Infinity Ward based off of the tried-and-true Q3 structure. So keep this in mind as you're shopping for a new video card, and don't overpower an older video game with multi-GPU graphics solutions because they will not produce the results you want.
In the next section we change gears and test to compare our group of video cards in Unreal Tournament 3. Please continue on to see how the Unreal Engine 3 performs with our test collection of products.