4 ms·
>The benefit of using a DDR3 interface instead of SATA/SAS or PCIe is lower latency because the SSDs sit closer to the CPU. The memory interface has also been d
by valarauca1 12y ago
>The benefit of using a DDR3 interface instead of SATA/SAS or PCIe is lower latency because the SSDs sit closer to the CPU. The memory interface has also been designed with parallelism in mind and can thus take greater advantage of multiple drives without sacrificing performance or latency. SanDisk claims write latency of less then five microseconds, which is lower than what even PCIe SSDs offer (e.g. Intel SSD DC P3700 is rated at 20µs).
Source: http://www.anandtech.com/show/8396/fms-2014-sandisk-ulltradimm-to-ship-in-supermicro-servers http://www.anandtech.com/show/8396/fms-2014-sandisk-ulltradi...
TL;DR about 4x faster then PCIe SSD's
- justincormack 12y agoAlthough it is apparently implemented via Sata on the module so there is scope to speed it up more.
- digikata 12y agoBut raw flash writes on the order of 1-2 milliseconds, so the 5 microseconds must be the latency to write to a ram cache inside the stick. I wonder what the latency would be for a write larger than the buffer. For that matter, how large is the buffer?
- valarauca1 12y agoIf you read the source you will see that no independent benchmarks have been done yet.
- digikata 12y agoThe article did update with a benchmark link comparing a couple of models to a fusion io card. http://www.percona.com/blog/2014/08/12/benchmarking-exflash-with-sysbench-fileio/ http://www.percona.com/blog/2014/08/12/benchmarking-exflash-... So the 95%, write latency is 1-1.5 msec for one model, and 2.5-3.5 msec for another model. Maybe representing SLC/MLC flash? 95% read latencies are maybe 350 or 250 usec.