Does anyone have any more info on the GDDR5 memory being used in the 4870? It seems to be running on a 900MHz clock with 3600MHz data rate, ie quad pumped, how is this - or have ATI sent a large cheque to Rambus to license some sort of XDR technology...
This is my understanding of it, based on tidbits I've gleaned:
ATI/AMD and their partner developed the GDDR4 and GDDR5 standards. This is probably why Nvidia hasn't moved to the GDDR4/5 standards... either ATI refuses to license the technology to them, or Nvidia refuses to purchase.
Yes, it is quad pumped, which is a cheaper solution than upgrading to a 512 bit memory bus for theoretically the same bandwidth performance. Also, when GDDR5 starts heavier production, it should be cheaper to manufacture than the prior GDDR levels, giving a further advantage to ATI in any price wars the competition may consider.