So I've decided to go with the 4870 now the question is right now do I buy one of the ATI Radeon 4870x2 now and buy a second later on? Or do I buy two ATI Radeon 4870's right now and run them into SLI. Now I understand that ATI uses the intel chipset with only two 8x PCIE2.0 channels but this is fine since those channels still aren't used fully. ( Why the heck does NVIDIA have 3 PCIE 16x channels when we can't even use one fully? I never got that. )
In addition does anyone have any recommendations for a good motherboard and cpu to support this setup? I'm looking a bit to the p45 or x48 chipsets and either a high end Core 2 Duo or a Medium High Quad Core.
First off, you don't SLI ATI video cards, you SLI Nvidia cards. And secondly, the P45 that does Crossfire does PCIe x8 when there's two. The X48 does the full x16. And x8 will limit the 4870's performance somewhat.
Buying one 4870x2 and upgrading later on might not be the best move. By then, there may be single card solutions that outperforms the 4870x2 for much less. What I would do is buy a single 4870, then Crossfire it with the 4870x2 later on.
You should get a X48 motherboard. If you're only going to game, a quad may not be worth the extra cash. I read somewhere that only 2% of all games now are quad-threaded, so if you're the type to upgrade often, go grab an E8200 and OC away.
Honestly the HD4870 is so good that I would just get one. That way you could stay P45, and save the $200-400 depending on the other choices to buy an entirelly new card sometime in the future. Considering you could sell your HD4870 for at least 50% of sticker price, that means that in only 6 months time you could be way ahead of the game.
And currently, there isn't any game out that the HD4870 can't handle quite well.
That's how I play anyway. Buy mid to upper mid, upgarde often.