Originally Posted by mechtech
The performance difference is negligible really. GDDR4 has higher clock speeds, but also higher latencies.
The performance difference is there, but memory bandwidth just isn't the bottleneck on the 3800 series, the core speed is.
The real advantage to GDDR4 is memory density, so you can get 1GB of RAM on a GPU, but again, the 256bit bus nullifies the benefit of 1GB memory.
All in all, the 3800 series doesn't really benefit from GDDR4 that much.
I dissagree, i have a gigabyte RAdeon 3870 with GDDR3, and i should be able to get 14K 3dmarks in '06 with my 4ghz E8400, but i cannot because of a huge limit in memory bandwidth due to limits in clock speeds. even with a 958mhz core clock on my card. GDDR4 is pulling clocks of 2.6ghz+ whereas i can only acheive a meisly 2.2ghz~ at max. ive been comparing with a system i built for a friend that is very close, cpu is a bit slower (3.6ghz) and so is the core on the radeon, but my card (958/2088) vs. his card (850/2400) is still right up there with my system, nearly neck and neck.