Valve's High Dynamic Range Explored

Day of Defeat Performance Tests

Half life 2 is one of those games that usually gives us pretty good framerates on a wide variety of cards. It's interesting to see how Day of Defeat: Source seems to up the ante (so to speak) in the graphics department, giving our cards a work-out even without the HDR effects enabled. The fact that the fps of all the cards without HDR enabled is similar suggests that there is some CPU limitation to the game. It's also safe to say that turning on the full HDR mode causes quite a significant performance hit, especially in the 6600 GT, the only 128 MB card that we tested.

In the past, we've noticed that ATI performs a little better than NVIDIA in Half life 2, and not surprisingly, we see the same thing here with Day of Defeat. While it's true that the 7800 GTX gets higher framerates than any of the ATI cards, keep in mind that NVIDIA's 7800 series is in a class above even the fastest ATI cards out now (although not for very long), and the fact that the framerates on the ATI cards aren't far behind says something here.

You can see that without HDR enabled, the ATI cards get better framerates than all of the NVIDIA cards except the 7800 GTX. This illustrates how well ATI handles this game engine, and the fact that all the framerates are fairly close together here imply some CPU limitation for this game.

Here, we see how the bloom effect starts to put a strain on the lower memory cards. The X800 and, in particular, the 6600 GT are the most memory-limited of these cards, but ATI's X800 does significantly better than the 6600 GT.

The only card that doesn't see a large drop in framerate with full HDR enabled is the 7800 GTX, followed closely by the 7800 GT. This shows that the newer architectures are able to handle Valve's HDR implimentation a little better than earlier hardware. There is also evidence that HDR uses up a lot of memory and/or bandwidth. Some sacrifices in quality/resolution will have to be made on 128-bit/128MB cards such as the 6600 GT in order to run this mode successfully.