The Inquirer has an article regarding the memory of NVIDIA and ATi their upcoming graphics cores (NV40 and R420). They write that they will support DDR 1, GDDR 2 and GDDR 3 memory, but that they will be sticking with GDDR2 at least at first. The reason for this is because DDR 1 is too slow and is too hard to clock above 1GHz.
GDDR 2 was sampled in Q3 2003 by Samsung and rated at 600 to 800MHz -- effectively 1200MHz to 1600MHz. Insiders have told us that Nvidia received 10,000 memory chips back in Q4 last year to prepare prototypes of its NV40 boards. We also learned that NV40 has 16 memory chips on board. Nvidia is aiming at a frequency of 750MHz -- or 1500MHz effectively -- but this depends on PCB quality and the number of layers. The first NV40 silicon-powered prototypes are currently meandering through the offices of special, beloved Nvidia partners, we are given to understand.
GDDR 3 may, in theory, be one of the options on the market but, if you ask around in knowledgeable circles, you will learn that this memory is in early sample stage and so neither Nvidia nor ATI could get enough chips for Q2 retail availability of the cards, however big their muscles.
It is expected that GDDR 3 will be ready by Q3 2004 so you might expect that the planned NV45 and the next ATI chip (R450 - R480?) will use this memory.
Micron is the only signed up member of the Dramurai to have GDDR3 memory specifications on their site. There, the company suggests that Q1 will be a good time for sampling and my guess is that they won't be ready for production before Q3. Clockspeeds for both GDDR 2 and 3 will be set in the range from 600 to 800MHz - effectively 1200 to 1600 MHz.
It’s interesting to see that 800MHz GDDR2 SDRAM has a latency of an incredible 1.25ns.
Both the NV40 and R420 cards and memory interfaces are 256-bit ones and by current estimates, this means that a card that uses 600MHz GDDR 2 memory would have between a majestic 37.5 GB/s to a magnificent 50 GB/s raw bandwidth.