Heh, I had the same problem with my nF4 and all the video cards I've had, lol.
Well, short answer is YES it can.
In my own experience: when the card runs way too hot (the case of the 4890, lol) they can burn or make the fans mal function (or any chipset around it) if they don't have enough space to "breathe" or they are being pressed. Is kinda obvious if it actually stops any mechanism, but it ain't when you see the fan active.
Anyway, since it's the southbridge I'll assume it doesn't have any active cooling (fans) so it might work a little hotter, but nothing more. If it actually MAKES your system unstable, i recommend getting an active fan for it. I got an ICEBRQ and it works flawlessly fine.
Hope it helps 8)
PS: Got some pictures of it, btw, in case you need :P
EDIT: Typo xP