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...
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.
The other thing is I thin it's not quad pumped the way that DDR is double pumped / dual data rate.
From my understanding it's two 32bit words simultaneously at 8 bit per pin (instead of the one of GDDR2/3/4 at 4 bit per pin) and then double pumped.
Message edited by TheGreatGrapeApe on 06-25-2008 at 10:04:58 PM
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Reply to TheGreatGrapeApe
That would be my understanding of it also TGGA. I have read a couple of articles on it but that one was the best i have seen in my view. I would call it Quasi Quad Data Rate Mactronix
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