I have an asus a8n-sli. I have a amd athlon 64 3500 cpu & 2gb of ram. I want to upgrade so i can convert videos quicker. I was considerinf upgrading processer to amd 64 x2 4800 & supping rhe ram to 4gb. Will this make any differwnce to the video converting speed or should i look at buying a new pc.
yes it will make an improvement, but prob. not enough of one for you to really notice.
I'm in the same boat as you (with an old AMD X2 CPU still) and honestly you are better off getting a more modern CPU and a motherboard that supports AM3 +
If you are looking to just convert video, the DDR3 memory, and newer AMD 6 core CPUs will help more than anything else.
The best thing about PCs is that you don't need to buy a new one... if you can just upgrade the components in it.