Sequential Read Performance

The sequential read test requests 128kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, and the drive is filled before the test begins. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 128KB Sequential Read

The RD400 delivers sequential read speeds on par with other PCIe 3 drives and almost three times the speed possible from a SATA drive.

Iometer - 128KB Sequential Read (Power)

The RD400 draws slightly more power than the Samsung 950 Pro. The higher performance of the PCIe drives makes them much more efficient than any of the SATA drives.

The 256GB RD400 jumps in performance between QD 4 and QD 8 where it tops out at the advertised speed, while the larger models show more modest increases during the second half of this test.

Sequential Write Performance

The sequential write test writes 128kB blocks and tests queue depths ranging from 1 to 32. The queue depth is doubled every three minutes, for a total test duration of 18 minutes. The test spans the entire drive, and the drive is filled before the test begins. The primary score we report is an average of performances at queue depths 1, 2 and 4, as client usage typically consists mostly of low queue depth operations.

Iometer - 128KB Sequential Write

The RD400 tops the charts for sequential write speed with a substantial advantage over both Intel and Samsung PCIe SSDs.

Iometer - 128KB Sequential Write (Power)

Unsurprisingly, the high performance comes with high power consumption as the 512GB and 1TB models both draw over 6W.

The 256GB RD400 shows constant performance across queue depths while the larger models show a slight increase from QD1 to QD2. The 1TB model wavers later in the test as thermal throttling occasionally kicks in, but even so it stays much faster overall than any competitor.

Random Performance Mixed Read/Write Performance
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  • tarqsharq - Wednesday, May 25, 2016 - link

    Interesting article as always. I had been hoping for a larger price gap between this and the Samsung 950 Pro. At current prices, I think the choice is fairly obvious unless you need a 1TB SSD. Reply
  • Chaitanya - Wednesday, May 25, 2016 - link

    You have a choice of Sandisk X400 as well if you want 1TB capacity in M.2 form factor. Reply
  • edzieba - Wednesday, May 25, 2016 - link

    There's also the OEM version of the OCZ drive, the Toshiba XG3, which is also available in a 1TB m.2 SKU. Reply
  • Lord of the Bored - Thursday, May 26, 2016 - link

    And who DOESN'T need a 1TB SSD? Reply
  • MrSpadge - Friday, May 27, 2016 - link

    I think you're mixing up "want" and "need". Reply
  • DanNeely - Wednesday, May 25, 2016 - link

    "Unlike most cheap adapter cards, the RD400's adapter draws power from the PCIe slot's 12V supply and converts it to the 3.3V required by the M.2 drive."

    PCIe slots provide 10W of 3.3V power directly. (I believe this was originally done to make converting legacy cards via a bridge chip easier.) Why would the card need to do any DC-DC conversion?
    Reply
  • Byrn - Wednesday, May 25, 2016 - link

    I'd assume that if they convert they can get cleaner 3.3V than if they use the feed through the PCIe slot, or that they can design in better resilience to sudden power demand changes...

    Basically, by converting I would have thought they can better fit the power supplied to the drive to the demands it makes.
    Reply
  • digitalgriffin - Wednesday, May 25, 2016 - link

    You can filter any volt feed with enough capacitors. But you lose power efficiency when you do. Reply
  • Alexvrb - Wednesday, May 25, 2016 - link

    Yeah but they're filtering the power either way so converting from 12V -> 3.3V is less efficient than using 3.3V to start with. But getting back to what Byrn was saying... Byrn, they don't have a choice: This drive draws too much power to use the 3.3V supply.

    Look at idle power figures in this article. ~2.5W @ 12V. At 3.3V that would already be pushing it (right around 9W already). Under a load it's going to draw too much. So they had to use the 12V rail.
    Reply
  • Wardrop - Wednesday, May 25, 2016 - link

    2.5 watts is 2.5 watts. If it's a higher voltage, it's less amps, and vice versa. I think you've confused watts with amps? Reply

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