PCIe SSD Faceoff: Samsung XP941 (128GB & 256GB) and OCZ RevoDrive 350 (480GB) Tested
by Kristian Vättö on September 5, 2014 3:00 PM ESTFinal Words
Since we are dealing with two fairly different drives, I will split the conclusion into two by beginning with the XP941. The XP941 is still the fastest client SSD and while the 256GB model does not provide the same performance as the 512GB one, it is still faster than any SATA 6Gbps SSD by a hefty margin. The 128GB XP941 is a different story, though. It is not really faster than the 128GB 850 Pro because at such small capacity the performance is mostly NAND limited, except for large sequential read transfers where the SATA 6Gbps interface is the bottleneck.
The good news is that RamCity has lowered its pricing since May. The XP941 still carries a premium over SATA SSDs, but it is now more competitive in price at less than a dollar per gigabyte. For US-based customers, finding the XP941 in stock can be a bit difficult; Newegg has both the 128GB and 256GB models listed, but they're on backorder; meanwhile the 512GB model is in stock at Amazon, but only at a highly inflated price of $750.
| Price Comparison (9/4/2014) | |||||||||
| 120/128GB | 240/256GB | 480/512GB | 960GB/1TB | ||||||
| Samsung SSD XP941 | $127 | $252 | $486 | - | |||||
| Plextor M6e | $120 | $220 | $420 | - | |||||
| OCZ RevoDrive 350 | - | $517 | $810 | $1,260 | |||||
| Samsung SSD 850 Pro | $130 | $200 | $400 | $700 | |||||
| SanDisk Extreme Pro | - | $180 | $350 | $570 | |||||
The RevoDrive is a totally different case. The performance is only better in some corner cases where the drive is fed with high queue depth or large transfer data, and in most typical scenarios it is outperformed by SATA 6Gbps SSDs. In the end, the RevoDrive 350 is nothing more than a pre-built 4-drive RAID array, so it is only faster in cases where RAID in general is a benefit (e.g. heavily parallel IO workloads).
Not only is the RevoDrive relatively slow, it is also super expensive. For the price of the 240GB RevoDrive 350, you could get four 128GB 850 Pros with twice the total capacity and higher performance since the 850 Pro is faster than any single SandForce drive. The same goes for higher capacity RevoDrives too -- it is simply way more affordable to buy a bunch of SATA SSDs and build your own RAID array. Even if you do not know how to create a RAID array, I am sure you can find someone to do it for $50, in which case you would still save money and get a faster RAID array with better drives.
All in all, for those who are in the market for a PCIe SSD, the XP941 is the only serious option. It is the fastest client SSD on the market and as long as your motherboard includes boot support for it, it is the best client drive that money can buy at the moment. I am very excited to get my hands on the SM951 (and other native PCIe SSDs) because the XP941 is already great, but when you add PCIe 3.0, NVMe, and V-NAND to the mix it will be one hell of a drive.
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Intervenator - Friday, September 5, 2014 - link
Need MOAR insight into the PCIe SSD market! Wheres it going? Any noticeable performance increased to the end user? Who are the players in the market? Non performance advantages?If AnandTech has already written an article regarding any of this, could someone please point me towards it?
Intervenator - Friday, September 5, 2014 - link
Oh, and great review.Kristian Vättö - Friday, September 5, 2014 - link
We haven't done an article that collects all bits of info into one, but you may find the following articles interesting:http://www.anandtech.com/show/8006/samsung-ssd-xp9...
http://www.anandtech.com/show/7843/testing-sata-ex...
http://www.anandtech.com/show/7520/lsi-announces-s...
http://www.anandtech.com/show/8147/the-intel-ssd-d...
http://www.anandtech.com/show/8104/intel-ssd-dc-p3...
frenchy_2001 - Friday, September 5, 2014 - link
>Where is it going?M.2 form factor using PCIe gen3 x4 for portable and consumer, PCIe cards, up to Gen3 x8 for Datacenter/server. Both running NVMe protocol.
I don't see much future for SATAexpress, as the 2 other competing standards cover all the use cases already (and better too).
> Any noticeable performance increased to the end user?
Not unless you do a LOT of parallel IOs. For consumer, there is a diminutive return past the original boost from switching to SSD (mostly from lower latencies). HDD to SATA SSD gave orders of magnitude improvements. SATA3 -> PCIe is only incremental compared to that. Unless you need this for a server, video processing or other big IO limited task, there will be little difference.
>Who are the players in the market?
Still the same: Intel/Micron/Samsung/Sandisk for professionals/servers using mostly in-house designs (intel P3700 for example).
Marvel and Sandforce have announced PCIe NVMe controllers. No products for those yet.
>Non performance advantages?
M.2 will be more compact. Power draw should be more optimized. NVMe should have lower processor overhead.
Impulses - Friday, September 5, 2014 - link
Thx for that.iwod - Saturday, September 6, 2014 - link
Since speed is a relative thing. The HDD to SSD leap were amazing. But that doesn't mean you cant feel the different between SSD @ SATA 3GBps and SSD@ 6Gbps. And with the recent controller improvement on Random / Seq RW, I can also feel the difference between SATA and NVMe PCIe SSD.But with the increase memory capacity, the time to fetch things SSD will also be lower since they are likely cached. So throughput may become less of a concern after PCIe SSD, and average response time will play a role. Luckily this is already being worked on for server SSD usage. So they will likly filter down once PCIe SSD becomes mainstream.
For the future I would like to see even lower active power consumption. I wonder if they could get it under 2W.
Friendly0Fire - Friday, September 5, 2014 - link
This makes me think that the SM951 with X99 will be one hell of a beast... I want one. Heck, the XP941 would already be amazing.GrigioR - Friday, September 5, 2014 - link
Is it possible to boot from those PCIe drives using a 775 motherboard (p35chipset)? Getting rid of Satall bottleneck would be awesome on my modded Xeon system.Kristian Vättö - Friday, September 5, 2014 - link
The SM951 likely won't be bootable since it is an OEM drive, but there will be retail PCIe SSDs that are bootable even in older systems (the Plextor M6e should be, for instance).GrigioR - Sunday, September 7, 2014 - link
Nice. Too pricey 1$/GB on the 256GB model... Since my motherboard is PCIe 1.0/1.1 it would run at 500MB/s max... That should not be that noticieable. My Samsung 840 120/128GB runs at +- 250-260MB/s (read)... At least if it were a PCIe x4 it would do 1000MB (bus speed). I`ll leave this the way it is for now. Thank you very much for your input. Now i know it is possible.