Then perhaps your question about "Why did ATI choose a narrow bus and GDDR5" would be better suited for ATI and not me.
I told you before that I understand how VRAM works, yet you felt compelled to go off on another tangential graphics lesson. All I am saying is that, at this point in the game, this "512 meg" thing seems to be overstated--at least when it comes to the 4800 series. We have a ton of games on the market running at the highest possible resolution with high amounts of AA, and it's not even phasing these cards. Whether or not it will in the near future, we will have to wait and see.
I see that as pretty short sighted. It doesnt take alot of memory seepage for performance to nose dive. What may scale well may not scale well in the future due to a completely artificial memory bottleneck. After using a significant amount of SLI configurations with 512 Megs, 768, 896 and 1 gigabyte. The higher the memory. The more consistent the experience. Due to never forcing texture data across the system bus. I've seen 9800GX2 Quad SLI cards deliver absymmal performance for the resolutions they are supposed to be augmenting. Once you start passing 1600x1200 the 512 cards start to slowly lose ground regardless of how well they scale. Yet they could be 80% faster than a 768 meg card at specific settings. The higher the memory. The less compromise.
I felt the "need" to point it out because any amount of texture data being constantly sent through the PCIE bus is a cause of what many people refer to as "Stuttering". You also are saying things like "Bandwith can make up for lower memory amounts". And that makes zero sense because its not true. So you either need to clarify or I'm going too object to such a statement. Because its completely untrue.