Open thread on the differences between DDR and GDDR anyone?
GDDR chips generally have a wider bus than DDR chips e.g. 32 vs 16 bits on GDDR5 and DDR3.
On GDDR5, reads and writes occur on a forwarded clock running at 4x the GPU base clock, while the data rate on DDR3 is only 2x the base clock. Essentially this means we get twice the data rate out of GDDR5 parts than we do out of DDR3 parts running at the same frequency.
These days GDDR5 is the standard memory used on graphics cars, while DDR3 is the standard for system memory on the motherboard. DDR5 isn't actually a JEDEC standard ;) ... at least not yet. DDR4 is! http://eetimes.com/electronics-news/4219194/Jedec-readies-DDR4-memory-spec-
Open thread on the differences between DDR and GDDR anyone?
GDDR chips generally have a wider bus than DDR chips e.g. 32 vs 16 bits on GDDR5 and DDR3.
On GDDR5, reads and writes occur on a forwarded clock running at 4x the GPU base clock, while the data rate on DDR3 is only 2x the base clock. Essentially this means we get twice the data rate out of GDDR5 parts than we do out of DDR3 parts running at the same frequency.
Some references: http://en.wikipedia.org/wiki/GDDR5 http://en.wikipedia.org/wiki/Ddr3 http://www.elpida.com/pdfs/E1600E10.pdf
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