I have a Dell I620 that I put the nvidia gt520 in. I am not happy with the card and want to upgrade. Is it feesable to put in a dual slot card? Also, Dell said I could not upgrade my PSU. Is that really correct or are they full of it? Seems like a PSU upgrade should not be a problem, but I heard Dell may have made some bios settings(which they conveniently locked us out of) so the upgrade could cause trouble. It is under warranty and I know they will not support it - but I need to know this any way.
Also, I have a Dell dimension 8400...Could I upgrade the PSU on that and upgrade that card to a dual slot?
I'm not familiar with that Dell. Could you tell me the wattage of your PSU so I can recommend and graphics card?
Vendors would limit your PSU upgrading ability by using an unusual or proprietary form factor: I had a Lenovo that I could not upgrade, due to its L-shaped power supply. You may find a larger PSU to fit your machine on Ebay, but it may be at great cost, and of questionable build quality.
You could attempt to move your componenets to a different case, as I am confident that the only thing preventing a power supply upgrade is being limited to something that actually physically fits.
I'm sure someone here can find a graphics card (probably even dual slot) that will work without requiring a PSU upgrade, just let us know more about the machine (specifically PSU, and number and type of motherboard slots, and how many are free)