I've been upgrading an old e521. So far, I've upgraded the RAM to 4GB, upgraded the PSU, and replaced the processor with an AMD 64x2 5800+; I'm not sure what to do about the graphics card. Is there any practical limit to what I can put in the box other than size of the card itself? I bought a GeForce GTS 250 and had to return it because it was a double profile card and as a result did not fit into the e521 case. I'm looking at getting a single profile GeForce 9800 GT to replace it, but I haven't made any final decisions yet. My concern is that the motherboard won't be able to handle a card released more recently.
And another question; I've heard conflicting reports about the reverse compatibility of PCI-E x16 2.0 cards in 1.x slots. What's the verdict?