Based on PC performance of comparable parts, in many games a Geforce 3 ti 500 was faster than a 4 ti 4200. They both were 250mhz parts, but the fastest geforce 3 had faster memory, while the slowest 4 had the extra geometry shader like Xbox. In the games that can hit higher resolutions (assuming there is no performance penalty) obviously bandwidth wouldn't be an issue. But at the time, Xbox's GPU was top tier. It had high fillrate, fast texture/shader pipeline, and a fast geometry engine that often couldn't reach it's theoretical maximum because of bandwidth.How would bandwidth hold back the XBox when it'll do 720p with a lot of games without increasing the bandwidth at all, just the RAM pool. Many just need a patch, no RAM at all. Resolution is directly tied to the GPU so seems there is plenty of bandwidth for something extremely taxing like that.
There was a multiplatform developer on here a while back that basically said most everything you could do on ps2 or GC could you do through brute force or software on Xbox. Most just didn't bother with the time to do it. Or the advantages for the other consoles wouldn't show onscreen because the Xbox advantages would be much more apparent.
This isn't to say that it was completely handicapped by it's bandwidth. It's just that when you compare it to PS2 or GC, with their ultra fast embedded memory, they were basically never bandwidth bound. They had bottlenecks elsewhere in the pipeline.