I would guess the 6800 LE only because it is 256bit instead of 128 bit.
In general (and ive yet to see an exception nor should there ever be), all 68xx class GPUS (that is, the NV40 series) feature 256bit memory interlinks. The 66xx class GPUS (the NV43s) feature 128bit links. Now within ght NV40s there are cards featuring 128MB and 256MB. The official breakdown (or at least as nVidia said it should be) is as follows
NV40
6800LE -- 8x5, 300/350, 256Bit, 128MB (G)DDR
6800NU -- 12x5, 325/350, 256Bit, 128MB (G)DDR
6800GT -- 16x6, 350/500, 256Bit, 256MB GDDR3
6800U -- 16x6, 400/550, 256Bit, 256MB GDDR3
NV43
6600 -- 8x3, 300/550, 128Bit, 128MB (G)DDR
6600GT -- 8x3, 500/500, 128Bit, 128MB GDDR3
It half to do with bandwith capabilty of the video card.
When I say 256 bit am not talking about the ram.
Yes you are talking about the RAM.