zarx said: So unless you have a source that 4Gbit GDDR memory chips will be available in the next few months. |
Are you kidding?
2008 news... "Presently Qimonda has 512Mb (16Mx32) GDDR5 chips at 3.60GHz, 4.0GHz and 4.50GHz clock-speeds in PG-TFBGA-170 packages in production."
The PS3 uses 8x512MB GDDR5 (or 4Gbit like you said) to get ~170GB/s.... GTX 680 uses 16 chips because they need a 512bits bus width for near 380GB/s brandwidth... it's easy to make maths.
8 x 32bits = 256bits bus width = 190GB/s at high speeds
16 x 32bits = 512bits bus width = 380GB/s at high speeds
nVidia choose 16 x 256MB chips because they need to reach 380GB/s bandwidth... not because there is no 512MB chip.