Currently in use at work:
Business Dell computers with only low profile slots available. Video cards = Several years old ATI X1550s.
An ECS Nvidia G220, not for the speed, but for the ram in it, 512Mb. It included low profile brackets, so no problems there.
The card doesn't fit in the damn space! The old card fits fine, having a very thin heat sink, but the new one protrudes about a centimeter wider than the old videocard's, my hard drive is limiting the space.
I intend to use the card in 2D only, no 3D games at all. So, if I switch heatsinks between the old and new videocards to make it fit, will the old one be able to keep the new card fresh? The workload may be 2D only, but I work 12 hour shifts and have between 40 and 200 windows open at any one time, mostly mainframe system consoles.
Had you bought another AMD card it might have been possible. But AMD and Nvidia tend to use different mounting schemes, so odds are the heatsink from the x1550 won't fit onto the GT220. You can try it and see, but I doubt it will work.