Growing rift between desktop and GPU...
can somebody from industry explain how they're able to scale graphics memory so high, especially GDDR5.

desktop
DDRAM 266-400
DDR2 533-1066
DDR3 1066-2000
mem cell clock rate improving marginally, especially recently - 200, 266, 250Mhz

GPU world
GDDR 400-750
GDDR3 800-2200
GDDR5 3600-5500
mem cell clock rate 400, 550, 687Mhz??

Furthermore, speeds of GDDR3 doubled from ~1000 for 6800/X800 in '04 to 2200 for 9800GTX 5 years later.
4870 launched just recently with 3600. 5870 already uses 5000. And Samsung 7000 chips already entering production: 224GB/s 256bit, up to 336GB/s 384bit for GT300!
THATS CRAZY REMARKABLE PROGRESS IN 5 SHORT YEARS SINCE 6800 LAUNCH.

Maybe AMD should start using GDDR3 or GDDR5 for desktop. With a couple PC3-1600 DIMM, you only get 25.6GB/s. 5870's GDDR5 would give you 80GB/s - 3x more.