I'm assuming you have a 7300GT as a video card. With that amount of RAM, I'd say you should get anywhere between 600-800 bucks. Depending on demand. I just saw 6 MPs with 5160s go for 615 EUR on separate sales locally.
My 3.0Ghz 1,1 MP:
64bit 6827: http://browse.geekbench.ca/geekbench2/view/452041
32bit 6146: http://browse.geekbench.ca/geekbench2/view/452030
Mac mini (Mid 2011) Intel Core i5-2415M 2.3 GHz (2 cores) seems to get 5884 on 32bit scores which is spot on with the 5150 1,1 MP.
BTW, I got my MP for $380 in a stroke of luck.
Sweetfeld: I'm currently looking to upgrade my memory on my MacPro 1.1.
Love this machine, but I need a few things:
1) memory: where should I buy from? Have you heard of a manufacturer called Buslink? Are they good?
2) the video card: I think I need to replace mine. My Apple Display won't turn off if I put the computer to sleep. If I put it to sleep, I have to now attach it to my laptop, then go back and hook it up with my MacPro, and then it will turn on. So, where did you find a good video card? How do I find one? What am I looking for? How do I install it?