I think we need to see some benchmarks
Im still skeptical... Ive never heard of CPUs having anything to do with texturing, so unless 32bit CPUs are limiting texture resolution somehow, why does a 64bit get better textures? I understand, speeding up the whole thing means you can add more details, but if the details arent something the CPU controls anyway, then you can increase texture resolution regardless of the CPU's power.
I honestly dont know what to think of this, I dont think we have had any 64bit games yet. Id love to see some benchmarks... it really doesnt make sense to me though.