My SLI'd and OC'd 460s are still going strong and will stay at the new socket 2011 build. 1gig per card is not a problem for me (yet) as my max resolution is 1920x1080.
On another note, it is unfortunately the time that fans in GTX 460s will start to fail. The fan in my primary card works but makes an awful noise above 40% speed.
Don't know about other makes of 460, mine is a reference design from sparkle.
My fan specs are as follows:
12V 0.40A Brand "D" 128015-SH2 EP (128015 is very common in vga fans)
5000 rpm max
75mm X 15 mm (diam X height)
mounting base 3 holes, 47mm apart
4-pin, 15cm cable
Searched the whole internet (twice) for a replacement and the best match is this model, two of which are in the post:
This is an NTK fan model FD8015U12S which is 0.50A (slightly stronger and faster) which *in theory* should make the more powerful fan spin in fewer rpms. On the other side of the fan (ebay listing) is an amd radeon sticker
Bought it from ebay
Generally speaking, the easiest way to find a replacement vga fan is ebay: Search for "vga fan 75 45" (diameter, mounting holes distance in mm) and most probably you will find what you need.
Will post results when the fans arrive and are installed.
EDIT: Aftermarket coolers are out of the question since all of them occupy another pci-e slot so you need 3 slots per card, 6 for sli.Edited by Silkman - 6/30/13 at 12:35pm