I am going to be building a gaming computer soon and i need some advice on the best performance i can get for my money. All i need is a new video card (i currently have a x1900xt 256mb), some new RAM (2GB or more), a motherboard, and a new CPU. I have a 20 inch monitor and i game at 1680x1050. If anyone can help me out that would be great.
I do not know if a quad core is the best for this build, in all seriousness if he is on a budget I do not think its going to benefit him. Plus, when will we be seeing games that take advantage of 4 threads? Probably not for a while.
I do agree, though, that he needs to keep the graphics card he has. Nothing short of a 8800GTS will really give a performance increase over that. Now all you (the OP) said you needed was RAM, motherboard, and processor right? What about the hard-drive, and the case? If your current hard drive is 5 years old or around there, I'd recommend replacing it too (all a hard-drive is really meant to last is 5 years). Also, do you have the power supply?
So with that in mind I'll recommend a setup that includes a HDD and case, but the RAM, processor and motherboard will still work otherwise. Another question is how overclocking adverse you are: if you can overclock you will save money (but will lose stability if you do not be careful). So hence there will be two builds I recommend: one for overclocking and one for not.
RAM: OCZ Gold Series 2GB (2 x 1GB) at DDR2 667 (PC2 5400): $89.99 (C4 latency and a 1:1 ratio at a 333FSB will give you a 3.33 gigahertz processor and really quick ram, you do not want to attempt 400 FSB on a $500 budget, so DDR2-800 ram is not going to be worth it here).
Total price: $508.99, with $30 in rebates available to you.
Now if you are doing a non-overclock build, I recommend the same components with two adjustments: no CPU fan, and instead of the E4400 we can use the E6550. That processor will debut at $163 and push 2.33 gigahertz to start. You may want to swap out the RAM I recommended (although that will still work) for something DDR2-800, like what Emp recommended. The reason is that the E6550 will run with only RAM as slow as DDR2-667, which is what the OCZ is. So the RAM I recommended in the overclock will be running right at its recommended speed from the git-go.
So you may even look at some cheaper RAM in order to save the difference between the first processor setup and this new one. Its about a $15 difference, so it should not be to hard to beat.