The ATI Radeon 5XXX Thread

[LordEC911]

that is assuming the 4870x2 has more bandwidth than the 4870... which it effectively doesnt... both cards mirror their counterparts memory afaik and hence the extra memory bandwidth is completely useless... if at all, its a minor boost...

dual gpu cards would be way less memory bandwidth limited than single gpu cards if the added bandwidth would really be useful... thats not the case, afaik its even the contrary, dual gpu cards are more bandiwdth limited than single gpu cards... thats why there has been all this talk about getting gpus to share their memory capacity and bandwidth. cause right now, there is double the mem and double the mem bw on a dual gpu card, but it doesnt result in higher overall bw and higher overall memory capcity...

in sfr there might be a boost from higher overall bandwidth of a dual gpu card... but even that is unlikely... and even if true, most of the time xfire and sli run afr cause it brings a notably higher boost...

As to your first parts, you are correct, dual GPU cards like the 4870x2 don't increase the bandwidth vs a single GPU card but it also doesn't decrease it.
Each 800SP/40TMU/16ROP RV770 has 115GBps of bandwidth vs a 1600SP/80TMU/32ROP RV870 that has 160GBps.
Basically you are, possibly, more than doubling the potential throughput of the 5870 while only increasing bandwidth 39%, which was my original point.
Sure you don't have the inefficiencies of AFR and a dualGPU setup but you also run into other potential problems/bottlenecks.

I just have a feeling that we are in for a few surprises when we actually get to take a look at the architecture and performance, there is obviously quite a bit of tweaks/info that we haven't heard about/thought about.

PS- Before those Vantage scores were leaked, there was talk about Cypress running near 4890CF, which would put it in the same league as a GTX295.