Random Read/Write Speed

The four corners of SSD performance are as follows: random read, random write, sequential read and sequential write speed. Random accesses are generally small in size, while sequential accesses tend to be larger and thus we have the four Iometer tests we use in all of our reviews.

Our first test writes 4KB in a completely random pattern over an 8GB space of the drive to simulate the sort of random access that you'd see on an OS drive (even this is more stressful than a normal desktop user would see). I perform three concurrent IOs and run the test for 3 minutes. The results reported are in average MB/s over the entire time. We use both standard pseudo randomly generated data for each write as well as fully random data to show you both the maximum and minimum performance offered by SandForce based drives in these tests. The average performance of SF drives will likely be somewhere in between the two values for each drive you see in the graphs. For an understanding of why this matters, read our original SandForce article.

Desktop Iometer - 4KB Random Read (4K Aligned)

The Ultra Plus gets off to a good start, doing very well in our low queue depth random read test, bested only by Samsung's SSD 840 Pro out of our list of contenders here.

Desktop Iometer - 4KB Random Write (4K Aligned) - 8GB LBA Space

Random write performance is pretty good but the Ultra Plus doesn't hit any of the insanely high speeds set by most of the modern drives. Note that its performance is equal to the Samsung SSD 830, which was a favorite of ours. Not having a first class showing here isn't a huge problem.

Many of you have asked for random write performance at higher queue depths. What I have below is our 4KB random write test performed at a queue depth of 32 instead of 3. While the vast majority of desktop usage models experience queue depths of 0 - 5, higher depths are possible in heavy I/O (and multi-user) workloads:

Desktop Iometer - 4KB Random Write (8GB LBA Space QD=32)

We don't see much scaling with higher queue depths, likely a limit of the Marvell SS889175's 4-channel implementation here.

Steady State 4KB Random Write Performance

SanDisk has a completely separate division that handles enterprise drives, but I was curious to see what steady state 4KB random write performance using a 100% LBA span would look like. To find out I borrowed from our Enterprise Storage tests and compared to the results from our OCZ Vector review. Note that many of these drives are enterprise focused and as a result do much better so don't get too turned off by the comparison:

Enterprise Iometer - 4KB Random Write

The Ultra Plus fares much better than I expected, nipping at the heels of the Vertex 4. The Vertex 4 used similar Marvell silicon so I'm not too surprised here.

Sequential Read/Write Speed

To measure sequential performance I ran a 1 minute long 128KB sequential test over the entire span of the drive at a queue depth of 1. The results reported are in average MB/s over the entire test length.

Desktop Iometer - 128KB Sequential Read (4K Aligned)

Like most drive vendors looking to address the light use client market, SanDisk's sequential read performance is actually really good.

Desktop Iometer - 128KB Sequential Write (4K Aligned)

Low queue depth sequential write speed is also quite competitive, both of these will help deliver a pretty decent client experience.

AS-SSD Incompressible Sequential Performance

The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers.

Incompressible Sequential Read Performance - AS-SSD

Incompressible Sequential Write Performance - AS-SSD

Higher queue depth sequential IO is still very good on the Ultra Plus. There's no penalty to using incompressible data as the controller does no real time data compression/de-duplication.

 

Introduction Performance vs. Transfer Size
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  • Beenthere - Monday, January 07, 2013 - link

    Few if anyone would be able to differentiate a noticeable actual system performance change no matter which one of the listed SSDs they chose. SanDisk hasn't yet learned how to dupe the benches but in due time their numbers will increase similar to the others.

    If you're going to buy an SSD you should do your homework so you know the liabilities and realities including reliability and campatibility issues, lost data, drive size change, etc. If you want an eye opener read the warranties on SSDs at the respective SSD mfg. websites.
    Reply
  • mrdude - Monday, January 07, 2013 - link

    "The drive PCB itself is very small, potentially paving the way for some interesting, smaller-than-2.5" form factors."

    That's the most interesting bit, I find. Those things are absolutely tiny. So tiny that it kind of makes you wonder if standardizing the NGFF cards is even worth it going forward. If you need small storage then you can just stick with the standard SATA connectors on an itsy bitsy drive.

    Very cool :)
    Reply
  • vol7ron - Monday, January 07, 2013 - link

    n-TB sizes that much more of a coming reality Reply
  • SmCaudata - Monday, January 07, 2013 - link

    I picked up a SanDisk extreme 240 last year for about 50¢ per GB and I'm happy. Even during black Friday I didn't see anything cheaper and this drive is fast. The difference between most ssd now is academic. User experience is nearly the same for average consumers. Reply
  • mayankleoboy1 - Monday, January 07, 2013 - link

    Isnt it the same that OCZ implemented in Vertex4 f/w 1.4 ? Reply
  • blowfish - Monday, January 07, 2013 - link

    So for XP users, would a drive that doesn't support Trim be the way to go, since MS decided not to add Trim to XP in order to push Win7? Reply
  • randinspace - Monday, January 07, 2013 - link

    Upgrading to Windows 7 (and pretending like 8 didn't happen even though it has enviable features...) is the way to go. Seriously speaking (upgrade), it's not like a drive that has TRIM support is going to be a bad thing even if you can't use it, but see the above comments about Sandforce controllers in general/Intel's 335 series SSDs in particular. Or even see the comments about hacking in TRIM support, IF YOU DARE!

    FWIW I'm very happy with the performance of my (240GB) 335. I'd probably buy another one to put in my laptop if they weren't going for $40 more than what I paid last month...
    Reply
  • dave_the_nerd - Monday, January 07, 2013 - link

    They all support TRIM. None REQUIRE it.

    If your OS doesn't support TRIM commands, you just have to find the drive with the best built-in GC routines. That used to be Sandforce, but I don't know anymore.
    Reply
  • kmmatney - Monday, January 07, 2013 - link

    With Samsung and Intel SSDs you can just run their toolbox software to do a manual TRIM. Iknow you can schedule it automatically with the Intel SSD Toolbox, and I think you can do that with the Samsung software as well. I've had a 40GB Intel SSD running on Windows XP for 2+ years and the TRIM scheduler works great. Reply
  • Flunk - Monday, January 07, 2013 - link

    If you want real performance you could make a versio of this that features two of these PCBs along with a RAID chip for enhanced performance. All in a 2.5" form factor would be quite compelling. Reply

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