Well, 425 mhz is what ultra is at. So, I'm technically just close to Ultra, with the scores I've been getting though, I'll just call it an Ultra. Also, Ultra's memory is 256 DDR3 @ 1,100mhz, and so is my card's.
That's cool that you managed to get the memory up 200MHz from it's original. Usually the memory is the hardest to overclock without good cooling on the actual vram chips. Nice OC man
I'd check your sources on that. When I was reading an article way back when to OC my GF2 they specifically said you'll notice more difference with the memory clocked up. They could clock up the core quite a bit, but you wouldn't get a noticable difference until you clocked the memory up as far as it could go.