I was thinking about upgrading my CPU to an AMD Athlon 4 X2 5400+ or 5600+. I was wondering if it would be worthwhile for the time being while I wait to get a quad core chip. Would my PC3200 (400MHz) be a significant bottleneck in my system restricting performance? I would be using it with my 8800 GTX which I've already ordered.My main reason for doing this is for FSX of course.

I'm not sure what quad core does for FSX? The main thing I wonder about hardware-wise is if DX10 implementation of FSX would allow better use of multi-graphics cards. Also I think the AMD/ATI DX10 cards are due out shortly? scott s..

It is pretty much a done deal as far as Crossfire/SLI being supported in FSX. It won't be. Like somebody already said, the performance improvement when using SLI in FSX is not even noticeable. The game was designed around multi-monitor support. I am pretty sure Crossfire/SLI will help you in a game like Crysis though.FSX will not really take advantage of Duel-core, let alone Quad-Core. In fact, I don't think anything really takes advantage of Quad-Core right now as far as gaming goes. I have read where Quad-Core CPU's are actually running slower than Duel-Core CPU's in some games. I would avoid a Quad-Core CPU for now, and save that for the upgrade you will do around two years from now (who knows what will be out by then?).Don't forget that upgrading with DX10 in mind also means you are upgrading your Operating System to Vista. Don't forget to add the huge cost of Vista in your budget especially if you are building a complete new system planning on running the Ultimate Version for $400.Waiting is a good idea in my opinion. There will more than likely be no DX10 games out until 2008, or maybe very late 2007 if we are really lucky. Crysis will get delayed for sure if it hasn't already been. Heck, FSX won't even be DX10 ready for several more months either, and that is supposed to be the Showcase game for DX10. If you were to wait, you will be able to buy a couple of 8800GTX for about the same price of one today since Nvidia will bring there next new DX10 card to the market whenever ATI brings their first.Look around several PC Magazine websites, and general PC Geek websites. Many people are trying to decide what to do as far as upgrading is concerned right now since Vista was released. You can pick out alot of useful information at some sites. Just remember that FSX is CPU intensive, so you need a fast CPU. Also remember that SLI/Crossfire won't help you play FSX, but it will give you better performance in many other types of games that you may play.