LRDIMM sales occur – and benchmarks
Inphi reported Q2 2012 results.
Inphi suggests sales of both 16GB LRDIMMs and 32GB LRDIMMs.
It is likely that most of these may be 32GB LRDIMMs, since 16GB LRDIMMs are non-viable vs. RDIMMs.
Inphi is shy about reporting benchmarks for LRDIMMs – saying they will be available second half of 2012.
Benchmarks for LRDIMMs should have been available prior to LRDIMM launch.
LRDIMMs exhibit 45% worse latency and 36.7% worse throughput at 3 DPC
LRDIMMs (which are a new standard and incompatible with DDR3 RDIMMs) exhibit significant performance impairment at 3 DPC compared to RDIMM-compatible HCDIMMs:
– LRDIMMs have 45% worse latency than HCDIMMs (235ns vs. 161.9ns for HCDIMMs)
– LRDIMMs have 36.7% worse throughput than HCDIMMs (40.4GB/s vs. 63.9GB/s for HCDIMMs)
And this is when HCDIMMs are run at a SLOWED down 1066MHz at 3 DPC (in order to match the lower max achievable speed of the LRDIMMs).
This comparison – at SAME speed – highlights the architectural weaknesses of the LRDIMM design irrespective of the speeds.
When compared at the MAXIMUM achievable speeds (LRDIMMs at 1066MHz at 3 DPC and HCDIMM at 1333MHz at 3 DPC):
– LRDIMMs have approx. 45% worse latency than HCDIMMs (235ns vs. 161.9ns for HCDIMMs)
– LRDIMMs have 40% worse throughput than HCDIMMs (40.4GB/s vs. 68.1GB/s for HCDIMMs)