We'll start the benchmarks off with one of the toughest games out there: Crysis. Since we're out to get playable frame rates, we can't go all-out with the settings. But we want the game to look good. So, while we chose Low settings to start, we upped the next round of results to include Medium quality textures, shadows, shaders, water, and sound. In Crysis, the most important settings for eye candy are shaders and shadows, so we went beyond that a bit. Let's see what happened.
Right out of the gate, we're seeing some interesting data. Apparently, the PCIe bus' additional throughput enables quantifiable performance gains, even with a mainstream card like the Radeon HD 4650, as as the PCIe Radeon HD 4650 is quite a bit faster than its AGP counterpart.
But look at how the older Radeon HD 3850 easily surpasses the other, more modern, contenders. This can only be attributable to the card's memory bandwidth advantage, with fast GDDR3 and a 256-bit memory bus compared to the Radeon HD 4650's 128-bit bus and slower DDR2. Note how the Radeon HD 3850 is bumping into what appears to be a CPU bottleneck at about 40 frames per second (FPS).
There is not much to see from the Radeon X700 unfortunately, as it isn't even able to deliver playable frame rates at 1280x1024 with settings turned down to Low.
At this point, it looks like the Radeon HD 3850 will remain the king of AGP, delivering essentially the same performance from 1280x1024 all the way up to 1920x1200. The Radeon HD 4650s are on the edge of playable at 1280x1024, but not at higher resolutions. This isn't as bad as it sounds because these cards are going into older computers, and a 1280x1024 resolution is probably typical of the displays these cards will be driving.
Let's stress the CPU a little bit more with the medium physics setting, which allows for smashing up in-game buildings.
Here is where we see the CPU bottleneck put an end to any dreams of lightning-fast gaming on our old Athlon X2 3800+ machine. The CPU's maximum capabilities have moved peak performance down to about 29 FPS, which will likely be considered unacceptable by most. In our opinion, the physics setting should be left at Low on older machines.