Will SH5 be DX10 game .

[Arclight]

Some games run in different modes. Crysis can be started in DX9 or DX10 modes, for example. Others have DX10 exclusive options. For example, World in Conflict has an option to enable shadows from clouds and dual-monitor support, only if the system running it has DX10 support.

Technically a game should be faster in DX10, but in practice it varies. The extra eyecandy may well end up costing a little more performance. I think it comes down to optimization really. A game that's done purely in DX10 probably has better performance, because there are more efficient ways of getting the desired effect. But since not everyone can run games in DX10 yet, they wind up doing most in DX9, with some extra DX10 features tacked on. I think that if there are any performance gains to be had like that, they're probably minor at best, more likely negligible.

Crysis runs slower in DX10 mode than in "very high"-hack DX9 mode.
(you can't normally set "very high" in Crysis in DX9, but you can change the settings for "high" preset to match those of "very high", effectively enabling "very high" in DX9)