Of the above cards, the performance of the 7300 GT will be the best but yea as you stated its DX9. However the 2.5k cards with DX10 wont give playable framerates anyway, but they do have better video decoders and hence cpu utilization for video decoding will be much less. I believe you can get a Radeon HD 3450 for arnd 2.5k as well. That would be the best buy of the DX10 category cards, would beat the 8400 GS. though heard that the 8600 GT is available for under 5k as well and would be well worth the extra money. Not sure of the price of the 8500 GT but the performance is not that much more than the 8400 anyway