Athlons are faster and more expensive. I don't know how much you want to spend, but my sister just ordered a nice system yesterday, complete except for monitor, for $610 shipped, 1.33 ghz athlon, 256 MB RAM, video card with TV output, etc, that I'll put together when it arrives.
I can't afford a new system, I was thinking of a new processor (with a new motherboard). I will spend a maximum of 150 pounds, I think that shoulb be about 200 dollars. But the less I spend the best, I mean that if there's not a huge difference I'll go for the cheaper.
Get a good motherboard. It is the heart of the PC.
If it does not work well, nothing else will.
Duron is to Athlon what Celron is to P4. A cheaper cut down version. As to the speed difference in CAD, I don't know but CAD is one of the areas the Athlon/P4 would be better than the cut downs.
A celeron is a cut down P3, not a cut down P4. A duron is really a cut down athlon.
You can probably afford this combo for $212 USD, but it still needs to get shipped.
ECS K7S5A SiSŪ 735 SOCKET A MOTHERBOARD - RETAIL $57.00
CRUCIAL MICRON 256MB 32x64 PC 2100 DDR RAM - OEM $35.00
AMD ATHLON THUNDERBIRD 1.33GHz 266MHz FSB SOCKET A PGA PROCESSOR - RETAIL with Heatsink and Fan - $120.00
from NewEgg.com. That's where I always buy my stuff.
SilentStrike: Thanks! that option sounds good ;) , I'll have a look.