GX-280 I have a older DELL computer?

no it won't slow it down. 32bit operating systems only address about 3-3.5GB of ram, so the other ram memory left over just won't be read or used.

Your computer doesn't support a 64bit os, due to the pentium 4, unless its a 64bit Pentium 4 Presler, which I doubt it is, so you won't ever use the full amount of ram installed in your PC.

wow, yeah it's going to repair they're each dell dimension motherboards. neither one is smaller than the following however the layouts are extraordinary, and certainly the 520 has much less integration in comparison to the 280, all in all it is valued at a shot if you have already got it. If no longer, get an extra motherboard for $forty and feature all of the more recent crap. Good success