During testing we found that the ATI X850 Crossfire cards were able to run at a resolution higher than 1600×1200, which is impossible according to ATI. This was once the key limitation of the X800-series-based CrossFire as the last things gamers wanted to do back in 2005, when most had CRT monitors, is to be stuck at refresh rate no higher than 60Hz when you playing games at a resolution of 1600×1200. If you use an LCD, you can overlook this drawback because 60Hz is as high as you are going to get. Many people skipped the X800 series do to this limitation and the fact that the cards did not support shader model 3.0. It now seems that with updated drivers the resolution limitation driver is no longer present.
Those that own an LCD screen and ATI video card may have noticed that the ATI driver, once installed and the system reboots, automatically sets the desktop resolution to the native resolution of the LCD. Towards the end of testing with X850 CrossFire (and not exceeding 1600×1200) the realization finally entered my head that the system was running perfectly at the native resolution of my Dell 2405FPW, 1920×1200 60Hz. Going back to all the hub-bub surrounding X850 CrossFire, the serious draw back to the solution was that it was limited to 1600×1200 60Hz.
After thinking about it for a minute I hypothesized that the monitor was running at a lower refresh rate, not that big of deal for an LCD but for CRT it would cause serious problems trying to do anything. Out of curiosity, I fired up FEAR and proceeded to test it at 1920×1200 just to see how much below 60fps it was doing. At High settings, it turned in 55fps. At lower visual quality settings, it repeatedly ripped off 100+FPS! I then decided to fire up Fraps and load Tomb Raider with Vsync enabled to see how much below 60fps it was running.
Surprisingly it ran at a steady 60fps! There was no tearing apparent and everything seemed normal! We contacted AMD.ATI about our findings and they thought it was weird, but didn’t seem too surprised as this product is no longer being produced. We thought it was interesting and worth a mention to those that still own one of these cards and is looking to grab a second to run CrossFire now that they are so inexpensive!