Performance

We tested the game in our standard graphics test rig, and used a reference clocked ATI Radeon HD 5870 running Catalyst 9.10 WHQL.

Intel Core i7 Test System

• Intel Core i7-965 processor (3.2GHz: 133MHz x 24)
  
• Asus P6T V2 motherboard (Intel X58 Express with three PCI-Express 2.0 x16 slots)
  
• 3x 2GB Corsair TR3X6G1333C9 memory modules (operating in dual channel at DDR3 1,349.4MHz 9-9-9-24-1T)
  
• Corsair X128 120GB SSD running 1.571 firmware
  
• Corsair HX1000W PSU
  
• Windows 7 Home Premium x86-64
  
• Antec Twelve Hundred Chassis
  
• AMD ATI Radeon HD 5870 1GB – operating at 850/4,800MHz using Catalyst 9.10 WHQL

As Nvidia currently doesn’t have any DirectX 11 hardware available, we didn’t have a rival to pitch the Radeon against, so we opted instead to see the difference DirectX 11 made. We ran the game’s built-in benchmark (which you can launch from the very bottom of the Graphics menu in the Options screen) to record the following scores:


The difference between DirectX 9 and DirectX 11 is clear, and it doesn't make for good reading for the new API. The average score in DirectX 11 is 30% slower than in DirectX 9. The story of minimum frame rates is even harder to ignore - in DirectX 9, the game is nearly 40% faster. Of course, this is a pre-release demo, and because of time constraints, we only tested one graphics card, at one resolution, but still, given all the talk of 'efficiency' that surrounded DirectX 11, it's a shame to see such a massive difference. Perhaps the game's one saving grace is that it's not that taxing to run - while there's a big difference between both modes, neither is slow.

There might be a big performance difference, but we'd be willing to overlook that to some extent if there was a big visual improvement. Let's take a look at some comparison screen shots of our own.


This is the opening of the benchmark. As we had to close the game down to force DirectX 9 mode and see some comparison, we used the time elapsed in the top right hand corner as a guide for when to hit the F10 key and make Fraps take our screenshots. This means that the fractions of seconds that our human-speed reactions have created minor differences in the image, but they're close enough for the results to speak for themselves.




We were expecting the lovely rippling effects in the flags to vanish without tessellation to smooth out their supple curves. However, all of the flags in the demo rippled just as convincingly in DirectX 9 mode as they did in DirectX 11 mode. Likewise, all of the textures looked the same too. You'd need a seriously keen eye and brown paper envelope full of cash from one of the creators of Dirt 2 to notice any real difference between textures in the two versions of DirectX.

Some minor differences can be spotted in the lighting effects, though. Both DirectX 9 and DirectX 11 mode do an admiral job of mapping the sunlight onto the surfaces of the cars. However, we felt that Direct X 11 rendered the beams from our local star in a slightly more accurate and cleaner fashion, making the light sourcing look more believable. Most noticeable is the cleanness of the shadow, particular when it's cast by the rear spoiler onto the bodywork - in DirectX 9 mode, the shadow has a chunky edge, whereas in DirectX 11, its edges blend away smoothly. Still, the differences are marginal, not easy to spot and not worth a 30fps cut to your frame rate.

While the tessellation is supposed to render the crowds in a smoother and more lifelike fashion, it's hardly a crucial improvement. Arguably, if you're driving slow enough to see the people in the crowds then you shouldn't be playing a racing game. Likewise, the realism of the water displacement is another touch that you just don’t notice while gunning along dusty roads in excess of 100mph.

Conclusion

After the epic disappointment that was DirectX 10, and a few promising DirectX 11 press releases and rumours floating around, we were hoping for a lot more than the Dirt 2 demo delivers. We should reiterate that this is a demo and as such the final game may see some improvement in terms of performance, be it on release or via patches later down the line. We should also point out that whether on DirectX 9 or DirectX 11 mode, the game looked considerably better than it did when we reviewed it on the Xbox 360, though this will come as no surprise to PC gamers.

We can’t help but feel that it will take a developer creating a game for DirectX 11 from the ground up before we really start to see its potential unlocked. In the meantime, if the Colin McRae: Dirt 2 demo is anything to go by, we’d take the perfectly decent execution and frame rate boost that DirectX 9 mode delivers.

Do you have a Radeon HD 5000 series card? Have you tried the demo? What do you think of DirectX 11? Let us know your thoughts in the forums.