So those first two are far better than my 8800GT ? Even though it has a 192 bus width ? (my card had 256)
8800 has gddr3 while the 500 series has gddr5... so yes. Vram doesnt become much of a bottleneck until higher resolutions anyways. What resolution do you game at?
The 560ti will put your 8800gt to shame.
edit: Thought i saw 560ti, not 550ti. 550 will be more similar to your 8800gt.