Re:Intel's roadmap for Optane SSDs with 1,000x performance
by vitus on Monday June 13, 2016 @11:36PM
(#11899572)
This is actually slightly incorrect. You seem to be calculating as if the clock rate were 3300MHz, even though the listed number in DDR (double data rate) is actually double the actual clock rate (IIRC, for marketing reasons).
On top of that, the CAS latency is given in cycles -- the cited CAS latency for DDR3-3300 is 16 cycles. Multiplying # cycles by time per cycle yields a value closer to 9-10ns. Note that this is the "first word" latency in this table.
- The other thing you may be talking about is this "bit time", which looks like it's simply inverse throughput. It's very important not to conflate throughput with latency.
On top of that, the CAS latency is given in cycles -- the cited CAS latency for DDR3-3300 is 16 cycles. Multiplying # cycles by time per cycle yields a value closer to 9-10ns. Note that this is the "first word" latency in this table.
- The other thing you may be talking about is this "bit time", which looks like it's simply inverse throughput. It's very important not to conflate throughput with latency.