Samsung SM951 (512GB) PCIe SSD Review
by Kristian Vättö on February 24, 2015 8:00 AM ESTAnandTech Storage Bench - Heavy
While The Destroyer focuses on sustained and worst-case performance by hammering the drive with nearly 1TB worth of writes, the Heavy trace provides a more typical enthusiast and power user workload. By writing less to the drive, the Heavy trace doesn't drive the SSD into steady-state and thus the trace gives us a good idea of peak performance combined with some basic garbage collection routines.
| AnandTech Storage Bench - Heavy | ||||||||||||
| Workload | Description | Applications Used | ||||||||||
| Photo Editing | Import images, edit, export | Adobe Photoshop | ||||||||||
| Gaming | Pllay games, load levels | Starcraft II, World of Warcraft | ||||||||||
| Content Creation | HTML editing | Dreamweaver | ||||||||||
| General Productivity | Browse the web, manage local email, document creation, application install, virus/malware scan | Chrome, IE10, Outlook, Windows 8, AxCrypt, uTorrent, AdAware | ||||||||||
| Application Development | Compile Chromium | Visual Studio 2008 | ||||||||||
The Heavy trace drops virtualization from the equation and goes a bit lighter on photo editing and gaming, making it more relevant to the majority of end-users.
| AnandTech Storage Bench - Heavy - Specs | ||||||||||||
| Reads | 2.17 million | |||||||||||
| Writes | 1.78 million | |||||||||||
| Total IO Operations | 3.99 million | |||||||||||
| Total GB Read | 48.63 GB | |||||||||||
| Total GB Written | 106.32 GB | |||||||||||
| Average Queue Depth | ~4.6 | |||||||||||
| Focus | Peak IO, basic GC routines | |||||||||||
The Heavy trace is actually more write-centric than The Destroyer is. A part of that is explained by the lack of virtualization because operating systems tend to be read-intensive, be that a local or virtual system. The total number of IOs is less than 10% of The Destroyer's IOs, so the Heavy trace is much easier for the drive and doesn't even overwrite the drive once.
| AnandTech Storage Bench - Heavy - IO Breakdown | |||||||||||
| IO Size | <4KB | 4KB | 8KB | 16KB | 32KB | 64KB | 128KB | ||||
| % of Total | 7.8% | 29.2% | 3.5% | 10.3% | 10.8% | 4.1% | 21.7% | ||||
The Heavy trace has more focus on 16KB and 32KB IO sizes, but more than half of the IOs are still either 4KB or 128KB. About 43% of the IOs are sequential with the rest being slightly more full random than pseudo-random.
| AnandTech Storage Bench - Heavy - QD Breakdown | ||||||||||||
| Queue Depth | 1 | 2 | 3 | 4-5 | 6-10 | 11-20 | 21-32 | >32 | ||||
| % of Total | 63.5% | 10.4% | 5.1% | 5.0% | 6.4% | 6.0% | 3.2% | 0.3% | ||||
In terms of queue depths the Heavy trace is even more focused on very low queue depths with three fourths happening at queue depth of one or two.
I'm reporting the same performance metrics as in The Destroyer benchmark, but I'm running the drive in both empty and full states. Some manufacturers tend to focus intensively on peak performance on an empty drive, but in reality the drive will always contain some data. Testing the drive in full state gives us valuable information whether the drive loses performance once it's filled with data.
The SM951 performs even strongly in our Heavy trace and presents nearly 100% improvement in data rate over the XP941. In full state the SM951 loses a bit of its performance, but that's normal and the drop isn't any bigger than in other drives. Despite the lack of NVMe, it's starting to be clear that the SM951 is significantly faster than its predecessor and any SATA 6Gbps SSD.
The average latency is also cut in less than half, which is actually a more substantial improvement than going from a SATA 6Gbps drive to the XP941.
The share of high latency IOs is also the lowest with only 0.06% of the IOs having a higher than 10ms service time.
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3DoubleD - Tuesday, February 24, 2015 - link
While this drive looks great and all, after all the problems the 840EVO has had, it is hard to get excited about big benchmark numbers from a Samsung drive... you never know if they will stay that way. That said, this drive is MLC and not TLC, so less chance of similar issues as the 840EVO. Still, Samsung has a lot of work to repair their reputation with their customers.theduckofdeath - Tuesday, February 24, 2015 - link
Yeah, they only have a bit more than 1/4 of the market. Really suffering from that snafu... I think you're overreacting just a bit... :)3DoubleD - Tuesday, February 24, 2015 - link
How could their past sales possibly have suffered from a problem that is ongoing and developing? How future customers react will depend on whether Samsung properly addresses the current issues. My comment is based on this fact.theduckofdeath - Tuesday, February 24, 2015 - link
I have an Evo 840 and since the performance restoration fix I have not seen any sign of performance degradation on my drive. And that fix was made in October last year.theduckofdeath - Tuesday, February 24, 2015 - link
And just to clarify hwo desperate your trolling attempts are. It took (a limited number of) users a year to realise there even could be issues. That's how rare and hard to notice it was, even though the Evo 840 is probably the most sold SSD ever.K_Space - Tuesday, February 24, 2015 - link
I am not sure if you are aware, however Samsung has released a recent statement to the effect that there remain issues with the 840 EVO drive and the above fix has not provided a permenant resolution:http://www.anandtech.com/show/8997/samsung-release...
I have an XP941 and SD Extreme Pro 480; it'd sensible to see how Samsung deals with the current situation at hand which may tip me and other enthusiasts (? <5% of their SSD sales) one way or the other.
extide - Tuesday, February 24, 2015 - link
Not really, Samsung has many other great drives, even older ones that are/were still great like the 830, 840 pro, etc. Couple teething issues on early TLC drives, thats pretty much what to expect ion this industry. The MAIN thing is that they are infact handling it, and not just shuffling it under the rug. IMHO thats far more important than anything else.smilingcrow - Wednesday, February 25, 2015 - link
"The MAIN thing is that they are in fact handling it"The MAIN thing for me is when they have HANDLED it and the solution sticks over time as only then would I trust one of their TLC drives again.
If that fails I expect a product recall which they haven't offered on the vanilla 840 yet which seemingly still has no fix. No recall = NOT handling it.
3DoubleD - Wednesday, February 25, 2015 - link
Teething issues - OK, that's fine, as long as they fix them, and that's all I've been saying; however, the verdict is still out as to whether they have fixed them or not, and that was my initial point.The minute they apply a permanent firmware fix or, if a firmware fix is not possible, a recall, then they will have handled it and I'd feel future Samsung purchases were justified. This obviously applies most strongly for Samsung TLC products, but how Samsung responds to SSD issues in general should be of interest of any current and potential Samsung SSD owner (TLC or MLC).
cm2187 - Tuesday, February 24, 2015 - link
What problems are you referring to?