There are some very old cards in this list (such as pre-DirectX 9 cards).

My gut feeling is that the Ivy bridge GPU is comparable with at least some of them.
It also has the hardware feature required for this level of cards.

I don't know if there are problems with older DirectX version.
I know they do DX 9 and 10, I don't know if intel is testing backward compatibility with existing DX 8 and older titles.

Hello "Sponge Bob",

So let me paraphrase your original question into two questions:
1) Are Ivy Bridge-based systems with HD2500 or HD4000 graphics powerful enough to provide a great gaming experience?
2) How do I optimize game performance on HD2500/HD4000 systems?

For the first question, "Jan dv" provided some useful information. You'll also want to do some web searching on your own for sites that provide benchmark info on relative "real world" performance of the various systems to see for yourself what's doable/possible with HD graphics. As an Intel employee, I'm obviously biased, but I know Intel and various game development companies have been working together to provide an enjoyable and engaging gaming experience on the Ivy Bridge platform. In other words, with some optimizations you should be able to create marketable games on Ivy Bridge-based systems without a discrete graphics card -- and you now have a much broader marketplace for your games.

For the second question, there are various resources that Intel provides that help you improve the playability of games developed for the Ivy Bridge platform:

• see the article "Using the product with Sandy Bridge and Ivy Bridge graphics", as it contains some hints and tips and additional links to Intel articles which describe "best known methods" for getting the most out of the platform: http://software.intel.com/en-us/articles/intel-gpa-using-the-product-wit...
• see "Practical Game Performance Analysis Using Intel® Graphics Performance Analyzers" article: http://software.intel.com/en-us/articles/practical-game-performance-anal...

Hope this helps! I welcome any follow-up questions from you.

Regards,

Neal

ps-> also, try your question on this forum: http://software.intel.com/en-us/forums/user-community-for-visual-computing