Excellent all-around characteristics, ships with heat sink (most of the other NVMe devices do not). Does not take the speed crown (the MyDigitalSSD is faster, but runs hot and will quickly throttle to a lower cap of 1.4 GB/sec). Performance is in the top quartile of the scale and the temperature is well regulated due to the heat sink. I would rate this device near the top, just behind Samsung's offerings.
There is one throttling issue. In long random read testing the device will throttle to 76C, and the firmware throttles a bit too much. It drops from 1.4 GB/sec all the way down to 177 MB/sec for 10 seconds, then back to 1.4 GB/sec for 30 seconds, and repeats. I'm not docking them a star for this behavior for several reasons. First, they ship with a heat sink and most other M.2 devices do not. Second, it takes a while to hit this behavior. Third, they throttle at 77C which is nice and conservative, meaning less chance of early flash failures due to heat, and other M.2 devices (the Toshiba and the MyDigitalSSD) throttle at much higher temperatures. Plextor is giving its customers a gift by throttling at 77C, I can't dock them for it even though they could do with an adjustment. No need to throttle all the way down to 177MB/sec for short bursts :-).
randread /dev/nvme6s1b <blksize> 100 16
16 threads - PLEXTOR_PX-256M8PeG (16GB area, uncompressable data)
blksize aggregate bw
------ --------------
512 62 MBytes/sec (94 MB/s @ 64 threads)
1024 124 MBytes/sec (135 MB/s @ 64 threads)
2048 248 MBytes/sec (271 MB/s @ 64 threads)
4096 494 MBytes/sec (542 MB/s @ 64 threads)
8192 808 MBytes/sec (899 MB/s @ 64 threads)
16384 1104 MBytes/sec (1160 MB/s @ 64 threads)
32768 1282 MBytes/sec (1281 MB/s @ 64 threads)
65536 1391 MBytes/sec (1385 MB/s @ 64 threads)
131072 1662 MBytes/sec (1664 MB/s @ 64 threads)
262144 1667 MBytes/sec (1660 MB/s @ 64 threads)
Sequential read @ 64KB block size: 1131 MBytes/sec
Sequential read @ 128KB block size: 1211 MBytes/sec
SPECIAL NOTES ON THE PLEXTOR
* Consistent sequential write bandwidth (16GB, QD1) of 656 MB/s)
* Consistent random read results.
* Slow temperature ramp (good), no immediate throttling after stabilization at 77C
during read test (but it takes a while for it to get to 77C). Note that
the Plextor was the only NVMe device to ship with a heat sink, so this
is the expected result. However, it did start to throttle when I let the test
run significantly longer (see above). I don't consider it a show-stopper though.
* Nice chipset queue setup for a M.2 device (16/16 instead of
8/8 or 7/7).
nvme6: <NVME-PCIe> mem 0xc7320000-0xc7323fff irq 40 at device 0.0 on pci4
nvme6: mapped 19 MSIX IRQs
nvme6: NVME Version 1.2 maxqe=1024 caps=00300030280303ff
nvme6: Model PLEXTOR_PX-256M8PeG BaseSerial P02652102851 nscount=1
nvme6: Request 64/32 queues, Returns 16/16 queues, rw-sep map (16, 16)
nvme6: Interrupt Coalesce: 100uS / 4 qentries
nvme6: Disk nvme3 ns=1 blksize=512 lbacnt=500118192 cap=238GB serno=P02652102851-1
| Hard Drive | 1 TB PCIE |
|---|
