The Mainstream Phoenix Rises: Samsung's 970 EVO (500GB & 1TB) SSDs Reviewed
by Billy Tallis on April 24, 2018 10:00 AM ESTMixed Random Performance
Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.
The Samsung 970 EVO is slightly slower than the OEM PM981 on the mixed random I/O test, but that still leaves the 1TB model very near the top of the chart, and the 500GB 970 EVO is only slightly behind the MLC-based 960 PRO.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The power efficiency of the Samsung 970 EVO trails the PM981 by a larger margin than performance alone did. The efficiency of the best MLC drives seems almost out of reach for TLC drives, except that the WD Black is in third place overall with 26% better efficiency than the 970 EVO.
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The Samsung 970 EVO's performance barely drops when writes are first added to the mix, and it grows at an accelerating rate through the rest of the test. The PM981 pulls ahead in the final phases with higher random write performance than the 970 EVO. The 960 EVO showed very flat performance until fairly late in the test, leaving it well behind the 970 EVO for overall performance despite offering similar performance at either end of the test.
Mixed Sequential Performance
Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.
The Samsung 970 EVO sets new records on the mixed sequential I/O test, with the 1TB model beating the Intel Optane SSD and the WD Black. The 500GB model is significantly slower, but still performs well for its capacity. Both models are much faster than the PM981.
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| Power Efficiency in MB/s/W | Average Power in W | ||||||||
The 1TB Samsung 970 EVO is essentially tied for second place in power efficiency on the mixed sequential I/O test, but the first place WD Black has a large lead. The improved performance of the 970 EVO over the PM981 is match by improved efficiency, but in absolute terms the 970 EVO is drawing more power than almost any flash-based SSD on this test.
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The performance of the Samsung 970 EVO on the mixed sequential I/O test wobbles around with an unusual pattern that mirrors that of the PM981 but little else. The 1TB 970 EVO shows the typical spike in performance at the end when the workload shifts to fully cacheable writes, but the test fulls the SLC write cache on the 500GB model and prevents it from getting that boost.
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cfenton - Tuesday, April 24, 2018 - link
I've been meaning to ask about this for a while, but why do you order the performance charts based on the 'empty' results? In most of my systems, the SSD's are ~70% full most of the time. Does performance only degrade significantly if they are 100% full? If not, it seems to me that the 'full' results would be more representative of the performance most users will see.Billy Tallis - Tuesday, April 24, 2018 - link
At 70% full you're generally going to get performance closer to fresh out of the box than to 100% full. Performance drops steeply as the last bits of space are used up. At 70% full, you probably still have the full dynamic SLC cache size usable, and there's plenty of room for garbage collection and wear leveling.When it comes to manual overprovisioning to prevent full-drive performance degradation, I don't think I've ever seen someone recommend reserving more than 25% of the drive's usable space unless you're trying to abuse a consumer drive with a very heavy enterprise workload.
cfenton - Tuesday, April 24, 2018 - link
Thanks for the reply. That's really helpful to know. I didn't even think about the dynamic SLC cache.imaheadcase - Tuesday, April 24, 2018 - link
So im wondering, i got a small 8TB server i use for media/backup. While i know im limited to network bandwidth, would replacing the drives with ssd make any impact at all?Billy Tallis - Tuesday, April 24, 2018 - link
It would be quieter and use less power. For media archiving over GbE, the sequential performance of mechanical drives is adequate. Incremental backups may make more random accesses, and retrieving a subset of data from your backup archive can definitely benefit from solid state performance, but it's probably not something you do often enough for it to matter.Even with the large pile of SSDs I have on hand, my personal machines still back up to a home server with mechanical drives in RAID.
gigahertz20 - Tuesday, April 24, 2018 - link
@Billy Tallis Just out of curiosity, what backup software are you using?enzotiger - Tuesday, April 24, 2018 - link
With the exception of sequential write, there are some significant gap between your numbers and Samsung's spec. Any clue?anactoraaron - Tuesday, April 24, 2018 - link
Honest question here. Which of these tests do more than just test the SLC cache? That's a big thing to test, as some of these other drives are MLC and won't slow down when used beyond any SLC caching.RamGuy239 - Tuesday, April 24, 2018 - link
So these are sold and markedet with IEEE1667 / Microsoft edrive from the get-go, unlike Samsung 960 EVO and Pro that had this promised only to get it at the end of their life-cycles (the latest firmware update).That's good and old. But does it really work? The current implementation on the Samsung 960 EVO and Pro has a major issue, it doesn't work when the disk is used as a boot drive. Samsung keeps claiming this is due to a NVMe module bug in most UEFI firmware's and will require motherboard manufactures to provide a UEFI firmware update including a fix.
Whether this is indeed true or not is hard for me to say, but that's what Samsung themselves claims over at their own support forums.
All I know is that I can't get neither my Samsung 960 EVO 1TB, or my Samsung 960 Pro 1TB to use hardware encryption with BitLocker on Windows 10 when its used as a boot drive on neither my Asus Maximus IX Apex or my Asus Maximus X Apex both running the latest BIOS/UEFI firmware update.
When used as a secondary drive hardware encryption works as intended.
With this whole mess around BitLocker/IEEE1667/Microsoft Edrive on the Samsung 960 EVO and Pro how does it all fare with these new ones? Is it all indeed a issue with NVMe and most UEFI firmware's requiring new UEFI firmware's with fixes from motherboard manufactures or does the 970 EVO and Pro suddenly work with BitLocker as a boot drive without new UEFI firmware releases?
Palorim12 - Tuesday, April 24, 2018 - link
Seems to be an issue with the BIOS chipset manufacturers like Megatrends, Phoenix, etc, and Samsung has stated they are working with them to resolve the issue.