It's not just Microsoft, it seems.  Here's an article citing the makers of FarCry & Crysys with the same behavior:

http://www.rlslog.net/crysis-makes-me-sick/#more-5980

Not only that, but it appears Crysys was intentionally tweaked to display crappier graphics on DirectX 9 than on 10.  Hackers have patched the Crysys demo to look exactly the same under DirectX 9, despite the maker's claims that they rely on features available only in DX10.

Which begs the question: why would a videogame manufacturer try to force customers to DirectX 10, available only on Vista?

Quote from: Ralf Maximus on November 20, 2007, 06:26 PM

Which begs the question: why would a videogame manufacturer try to force customers to DirectX 10, available only on Vista?

Duh?

Why would DX10 be Vista-only, when there's no reasons it couldn't be implemented for XP?

Why was Age Of Empires III artificially XP-only?

The primary difference being AOE is a Microsoft product, Crysys is not.  That MS would do this makes a twisted, evil kind of sense.

But how to explain the behavior of an independent company who (one would assume) benefits most by supporting DX9?

But how to explain the behavior of an independent company who (one would assume) benefits most by supporting DX9?

nVidia invested a lot of man hours helping Crytek with the technical side of Crysis, the game runs great on a 8800 GT, the new and impressive graphic card from them... connect the dots

And Crytek now says DirectX 10.1 (supported by the new Radeon 38xx) it's not a big deal. More signs!

It happened before. Halo 2 was exclusive for Vista... until hackers made it run in XP. IIRC Age of Empires II could not run under Windows 2000 (see a trend with Ensemble Studios/Microsoft games?), Doom III was NT-only, until someone learned to use an hex editor, and discovered why it could not run (a simple API that was named differently under NT OSs), etc.

Here are another set of benchmarks, showing on average a 24% slowdown of Vista compared to XP. The benchmarks are aimed at windows virtualisation on OS X, but they tested straight bootcamp installs of XP and Vista (thus native):

http://www.mactech.com/articles/mactech/Vol.24/24.02/VirtualizationBenchmark/

I suspect that is comparing the Macbook to the Lifebook - 0.03 clock slower but 2X the memory.