Modern graphics cards have obscene amounts of memory bandwidth as it is, and their successors only seem poised to break new records. In fact, Hynix recently announced a new GDDR5 memory chip it claims to have the highest performance and density on the market. This chip can pack 2Gb (256MB) of data and withstand an impressive 7Gbps data rate.
This isn't quite the first GDDR5 device to hit 7Gbps—Samsung already reached that milestone in February, but that was with a 1Gb, 50-nm part. Hynix built this latest chip using 40-nm process technology, and it claims the increase in density didn't hurt power consumption. Quite the contrary; the new device operates at 1.35V, and it purportedly draws 20% less power than "preceding memory solutions using 50nm class technology."
What's the point of a 7Gbps, 2Gb GDDR5 chip? If my math is right, slapping some of Hynix's new GDDR5 on the Radeon HD 5870 and running it at full speed would hypothetically increase the card's total bandwidth from 128GB/s to about 224GB/s—and that's with a 256-bit interface. I believe the card has eight memory chips (each with 32-bit I/O), so this hypothetical substitution would also give us 2GB of graphics memory instead of 1GB. Not bad, right?
We may not see that kind of memory used on current-generation hardware, though. Hynix says it only intends to start mass-production of 2Gb GDDR5 silicon in the second half of next year.