Intel SSD 750 PCIe SSD Review: NVMe for the Client
by Kristian Vättö on April 2, 2015 12:00 PM ESTMixed Random Read/Write Performance
Mixed read/write tests are also a new addition to our test suite. In real world applications a significant portion of workloads are mixed, meaning that there are both read and write IOs. Our Storage Bench benchmarks already illustrate mixed workloads by being based on actual real world IO traces, but until now we haven't had a proper synthetic way to measure mixed performance.
The benchmark is divided into two tests. The first one tests mixed performance with 4KB random IOs at six different read/write distributions starting at 100% reads and adding 20% of writes in each phase. Because we are dealing with a mixed workload that contains reads, the drive is first filled with 128KB sequential data to ensure valid results. Similarly, because the IO pattern is random, I've limited the LBA span to 16GB to ensure that the results aren't affected by IO consistency. The queue depth of the 4KB random test is three.
Again, for the sake of readability, I provide both an average based bar graph as well as a line graph with the full data on it. The bar graph represents an average of all six read/write distribution data rates for quick comparison, whereas the line graph includes a separate data point for each tested distribution.
The SSD 750 does very well in mixed random workloads, especially when compared to the SM951 that is slower than most high-end SATA drives. The performance scales quite nicely as the portion of writes is increased.
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Mixed Sequential Read/Write Performance
The sequential mixed workload tests are also tested with a full drive, but I've not limited the LBA range as that's not needed with sequential data patterns. The queue depth for the tests is one.
In mixed sequential workloads, however, the SSD 750 and SM951 are practically indentical. Both deliver excellent performance at 100% reads and writes, but the performance does drop significantly once reads and writes are mixed. Even with the drop, the two push out 400MB/s whereas most SATA drives manage ~200MB/s, so PCIe certainly has a big advantage here.
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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-00000Redstorm - 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.