building new computer or alternatives?

I currently have a soy vaio... 3.0 ghz intel HT processor, 1 gig of ram, ati x800xl pci-e, standard case and everything. Basically this computer isn't cutting it, I want a whole new one that'll be upgradable with SLI, a new processor, better case. This computer has horrible startup times, games don't run THAT smooth. Basically I'm asking should I build a whole new computer from scratch? Or should I just buy a new motherboard and processor, but keep everything else? How much money do you think I could get for this computer?

Also I was wondering just how powerful AMD processors are? Can you make a comparisson between the two? I heard a 2.2 amd is as powerful as a 3.2 intel or something, could someone please explain?

 

Wow! Your system isn't good enough? Those are some decent specs you have there! I would recommend that you follow the instructions at this link to tweak the system for performance. Also, to help boot times, you might try deleting all files in C:\Windows\Prefetch. You could also consider a hardware upgrade, or following the instructions in the Overclocking Guide. You should DEFINITELY be able to squeeze more life out of that rig. (probably with only your thumb and index finger)

Should you build a new computer from scratch? I don't know. Its fun, and always a learning experience, but to do it because the current machine is a little slow? I'm not sure about that. If you were to sell the current machine with the OS license, you could probably get a few hundered bucks for it. I'd ask for at least a grand. (speaking in Canadian dollars)

AMD processors are supposed to be more powerful. Hence their naming scheme. For example, the Athlon 3500+ is supposed to be as quick as a 3.5GHz processor, even though it only runs at 2.2GHz. A 4800+ is supposed to be as quick as a 4.8GHz. There is a discussion on how AMD accomplishes this at this link.