How fast is a single core of an Athlon 4200+ x2 compared to a 4200+

Just bumping this, as there's an Ebay auction ending soon and I'm not commited yet

since there is no single core 4200+, I assume you mean 3200+ vs x2 4200+.
Here's some specs links:
http://www.cpu-world.com/CPUs/K8/AMD-Athlon%2064%203200...(ADA3200BWBOX).html
http://www.cpu-world.com/CPUs/K8/AMD-Athlon%2064%20X2%2...(ADA4200BVBOX).html

but have one core in use constantly. So will I end up with less performance?
I don't understand your question and you shouldn't have one core always at 100% use under normal circumstances.

But each core of the 4200+ is faster than the one core of the 3200+. an improved performance in all circumstances

Ah, my mistake on the non-existent 4200+.

Well, thankyou very much for answering my question, that's perfect. It now looks like a wise purchase.

To explain your query, it relates to another thread where I found out everything but what you've just answered: I have a media center box which I also use for browsing. I wanted to use MCE buddy to comskip, and also encode for portable devices, and although you can schedule it, I encountered difficulty with this.

So basically, I wanted MCE buddy to be constantly encoding one one core, while the other is free for Firefox and WMC. Looks like this is my prefect solution, perhaps along with another 1tb spinpoint.

I only have 1Gb of RAM too, but I can't imagine I need a great deal for what I do.

Yep, it's a great solution for you then. And each core will be 2.2GHz vs the old single 2GHz you have now.
And yeah, unless you are running vista or 7, no need for additional ram.

Ah, I am running 7. So 1gb could be a problem?

I usually keep task manager open to peek at from time to time, but I've never seen the RAM usage excessively high. However I assumed the encoding would be processor intensive and not RAM intensive.

I'd think so too. I can't really comment since I've never run windows 7 with 1GB of memory but my system used to be a 3200+ overclocked to 2.5GHz, 2GB of ram and onboard graphics. I had no trouble doing what I needed but I don't really remember.

Test out doing what you want to do with your current system. If your ram usage isn't excessive, than you will be fine.

Still, at least 2GB I recommend. You could pick up another GB for about $25.

Great, thanks for your help Enzo