New CPU or new PC

Hey guys, wasn't sure whether to put this here or hardware tools but since it's more about setup than tools figured I'd put it here and let it be moved if need be.

I've just gotten into 2-boxing in wow (used to 3-4 box in EQ many years ago) as a test before moving into more party members for gear and rep grinding and it's not too bad but I'm considering what to do with my hardware at this stage.

I'm currently running with AMD X2 3200+, 2Gb RAM, 7800GTX SLI, 22" LCD as my main gaming pc and have to by a new system in the next few months as a work-related tax write off which will likely be Q6600, 4Gb 1066MHz RAM, 8800GTS SLI, 2 x 22" LCD but I'm wondering if I could get away with just upgrading my CPU to an AMD X2 6400+ (for about $260) and acheive a reasonable framerate with 5 accounts or if I should just bite the bullet now and do the full CPU, MB, RAM, Video upgrade (for about $2k).

What will you be doing with the old PC after you upgrade? Might be worth spending the money on the upgrade if you will still end up using it. If you keep it you also open up the option of using 2 boxes with the 5 characters spread over them which I think is easily achievable with KeyClone.

Your biggest problem is going to be the 2GB RAM I think. I am running 5 accounts in Azeroth at the moment and getting up to that 2GB figure. Soon as you go over it you will start hitting the page file hard and that is going to be painful.

Yeah, I currently have another pc running a 1st ed AMD64 and 9700xt that I use as a windows 2k3 server + file server and I'll be replacing that with the current system (ie moving the HD's across, using it's case and monitor etc) when I finish the upgrade. I was already considering using it for a second keyclone pc too and upping it to 4Gb but if I can avoid that with the new system I'd be more happy.

Since it's just after xmas I'd rather not be outlaying the whole parts upgrade in one hit so my plan was to buy the new mb, cpu and ram, put it into the current system case and take one of the 7800's into it for the time being while then moving the current mb, cpu, ram and 1 7800 into the file server then as I get the 8800's I can move things back.

Guess I know I have to get the new system eventually but perhaps just getting the new cpu and 2Gb of RAM this week would be the best option, see how that goes for increasing performance and then if I still want more go ahead and build the new system up...the 6400+ wont go to waste after the upgrade anyway since it will help increase encoding and transcoding on the fileserver.

[EDIT]

Bleah, just checked and seems the 6400+ is for AM2 anyway so if I want to go past a 4400+ I need to get a new MB to replace my 939 board....guess my decision is made for me :)

Your motherboard/chipset is the core of your system. Without the underlying FSB speeds and well-written quad-core support, you won't really take advantage of the Q6600. For the money, though, the X2 CPU upgrade will be the biggest one-shot in the bunch. You'll definitely get a much larger bump with the full upgrade but the CPU-only route is definitely a worthwhile option assuming your current motherboard supports it. For running 5 WoW clients, though, you will definitely want to plop another 2GB of RAM in that thing. Prices being what they are, you're probably better off either waiting until you can just upgrade it all or swapping in the motherboard, CPU and RAM first until you can afford the rest (assuming money is an object).