Sequential Read Performance

Our sequential tests are conducted in the same manner as our random IO tests. Each queue depth is tested for three minutes without any idle time in between the tests and the IOs are 4K aligned similar to what you would experience in a typical desktop OS.

Iometer - 128KB Sequential Read

In sequential read performance the SM951 keeps its lead. While the SSD 750 reaches up to 2.75GB/s at high queue depths, the scaling at small queue depths is very poor. I think this is an area where Intel should have put in a little more effort because it would translate to better performance in more typical workloads. 

Intel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)

 

Sequential Write Performance

Sequential write testing differs from random testing in the sense that the LBA span is not limited. That's because sequential IOs don't fragment the drive, so the performance will be at its peak regardless. 

Iometer - 128KB Sequential Write

The SSD 750 is faster in sequential writes than the SM951, but the difference isn't all that big when you take into account that the SSD 750 has more than twice the amount of NAND. The SM951 did have some throttling issues as you can see in the graph below and I bet that with a heatsink and proper cooling the two would be quite identical because at queue depth of 1 the SSD 750 is only marginally faster. It's again a bit disappointing that the SSD 750 isn't that well optimized for sequential IO because there's prcatically no scaling at all and the drive maxes out at ~1350MB/s. 

Intel SSD 750 1.2TB (PCIe 3.0 x4 - NVMe)
Random Performance Mixed Read/Write Performance
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  • magreen - Thursday, April 2, 2015 - link

    darkgreen, are you talking about a G1 without TRIM or a G2 with TRIM support?
  • darkgreen - Friday, April 3, 2015 - link

    I had a G1 without TRIM. The Intel fix was based on some ancient shareware (FreeDOS!) that wouldn't work with many modern motherboards and in some cases left drives bricked. It was well reported at the time (see my comment above for a google search that returns articles), but lots of people wound up with X25-Ms that were useless. If you weren't an enterprise customer the Intel response was "tough luck." No refunds, no replacements, nothing. In all fairness I'm sure Intel would love to be able to support consumers, but they probably aren't set up for it in their storage area because it's just not a big area of their business bottom line.
  • magreen - Sunday, April 5, 2015 - link

    Yeah, it seems like the G1 owners got screwed. (I have a G2 and G3 and they've both been great. Sorry they screwed the early adopters.)

    In Anand's words from 2009 when the G2 was released:
    "TRIM isn’t yet supported, but the 34nm drives will get a firmware update when Windows 7 launches enabling TRIM. XP and Vista users will get a performance enhancing utility (read: manual TRIM utility). It seems that 50nm users are SOL with regards to TRIM support. Bad form Intel, very bad form."
    http://anandtech.com/show/2806

    "Overall the G2 is the better drive but it's support for TRIM that will ultimately ensure that. The G1 will degrade in performance over time, the G2 will only lose performance as you fill it with real data. I wonder what else Intel has decided to add to the new firmware...

    I hate to say it but this is another example of Intel only delivering what it needs to in order to succeed. There's nothing that keeps the G1 from also having TRIM other than Intel being unwilling to invest the development time to make it happen. I'd be willing to assume that Intel already has TRIM working on the G1 internally and it simply chose not to validate the firmware for public release (an admittedly long process). But from Intel's perspective, why bother?

    Even the G1, in its used state, is faster than the fastest Indilinx drive. In 4KB random writes the G1 is even faster than an SLC Indilinx drive. Intel doesn't need to touch the G1, the only thing faster than it is the G2. Still, I do wish that Intel would be generous to its loyal customers that shelled out $600 for the first X25-M. It just seems like the right thing to do. Sigh."
    http://www.anandtech.com/show/2829/11
  • Redstorm - Thursday, April 2, 2015 - link

    Could you elaborate on this (although there appears to be an NVMe version too after all) of the SM951. As looking at the numbers if NVMe even slightly improves the SM951 it would make it a better choice, and the form factor being M.2 makes it much more attractive.
  • Kristian Vättö - Thursday, April 2, 2015 - link

    Ganesh received an NVMe version of the SM951 inside a NUC and I've also heard from other sources that it exists. No idea of its retail availability, though, as RamCity hadn't heard about it until I told them.
  • eddieobscurant - Thursday, April 2, 2015 - link

    if i'm not wrong the nvme version has p/n MZVPV256HDGL-00000 for the 256gb model while the ahci version has p/n MZHPV256HDGL-00000
  • Redstorm - Friday, April 3, 2015 - link

    Thanks looks promising , found this with verbage suposidly from RAMCity that they will ship in May.

    http://translate.google.co.nz/translate?hl=en&...
  • Redstorm - Friday, April 3, 2015 - link

    So no real proof that they exist then.
  • eddieobscurant - Thursday, April 2, 2015 - link

    Kristian, there is a DRAM difference between the two models. The 400gb has 1gb DRAM while the 1.2tb model has 2gb. Do you think it plays a big role in terms of performance between the two models.

    Also is there a way to reduce the overprovision in these drives? I would prefer 80gb more on the 400gb model over less consistency.

    When will you review the kingston hyperX predator, and when will samsung release the sm951 nvme? Q3 or sooner?
  • KAlmquist - Thursday, April 2, 2015 - link

    The 400gb model shouldn't need as much DRAM because it has fewer pages to keep track of. But there's no way to know how the 400gb model will perform until Intel sends out samples for review.

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