Mixed Random Read/Write Performance

For full details of how we conduct our Iometer tests, please refer to this article.

Iometer - Mixed 4KB Random Read/Write

In mixed 4KB random performance the 2TB Pro shows rather significant gains over the 512GB model. I was always surprised how poorly the 850 Pro performed in this test, so it's good to see Samsung paying attention to this, especially since the performance increase comes with dramatically improved power efficiency.

Iometer - Mixed 4KB Random Read/Write (Power)

Samsung 850 Pro 2TB

The 512GB Pro had performance and power issues once over half of the IOs were writes, but the 2TB model shows quite optimal performance scaling.

Mixed Sequential Read/Write Performance

Iometer - Mixed 128KB Sequential Read/Write

In mixed sequential workload performance of both the 2TB Pro and EVO is further improved with the Pro topping the chart. The 2TB EVO is again more power efficient than the 1TB model, whereas the 2TB Pro consumes only a little more power than the 512GB model (this was expected because large sequential IOs utilize multiple dies and with 2TB having more NAND there are more dies drawing power).

Iometer - Mixed 128KB Sequential Read/Write (Power)

The improvement has been in the critical 60/40 and 40/60 distributions. Quite a few drives have an infamous "bathtub" curve where performance severely degrades, but the 2TB Pro and EVO are fairly consistent though all distributions. It's great to see Samsung improving mixed performance because typically it has been an area that has been forgotten in client SSDs, but under real world workloads IOs tend consist of both reads and writes.

Samsung 850 Pro 2TB
Sequential Performance Idle Power Consumption, ATTO & AS-SSD


View All Comments

  • twizzlebizzle22 - Thursday, July 23, 2015 - link

    Damn, we are in the future here. Roll in the day when my media storage drives are all SSD.

    Interesting as to why they managed to double the drive durability from 150TB to 300TB. That's pretty substantial.
  • joex4444 - Thursday, July 23, 2015 - link

    Durability is the amount of data that can be written to the drive Samsung is guaranteeing can be written to it during its life. It's just related to the number of times a chip can be completely rewritten. If you double the capacity, you double the number of chips, and therefore you double the durability. Reply
  • lilmoe - Thursday, July 23, 2015 - link

    Sure, but Samsung is also setting the older 512GB and 1TB at 300TB endurance rating up from 150TB previously, which is nice. Reply
  • SleepyFE - Friday, July 24, 2015 - link

    If i'm not mistaken that was a marketing move. The EVO was sold as 150 so that people who needed more would buy PRO. There was a super punishing SSD test half a year back (a bit less maybe) where they tested how much the drives can take before the cells give up and even the EVO held out beyond 300. So they didn't really manage to improve anything, they just decided to extend their guarantee. Reply
  • leexgx - Saturday, July 25, 2015 - link

    EVO not as reliable as the Pro (TLC EVO vs MLC PRO,) the pro drive never failed with bad data it silently failed at 2PB

    the endurance is for warranty before where they have found errors have cropped up, the PRO drive use MLC so is reliably less error prone (as in they handle any minor errors better then TLC) then EVO under extreme loads (drives might look the same but the flash is not)
  • leexgx - Thursday, July 23, 2015 - link

    sorry if this is been asked before, is the 25% OP been done via the ATA command that allows you to set amount of useable space or are you just partitioning it (both after a Secure erase) Reply
  • Samus - Thursday, July 23, 2015 - link

    You don't even need to go that far. The Samsung Magician toolbox allows you to set a RAW OP "partition" Reply
  • leexgx - Thursday, July 23, 2015 - link

    i looked online i guess it worked as i thought it would, you can use ATA LBA limit command to hard limit the OP space or just make the partition say 20GB less then the size of the SSD (or what ever size you want) this is assuming its a fresh drive or secured erased state, but the thing is TRIM does the same thing any way (assuming you don't fill the drive so it runs out of space) if you cant use TRIM then you need to set higher OP space (recommended any way) Reply
  • TEAMSWITCHER - Thursday, July 23, 2015 - link

    Not quite yet.... I've been limping along with a pair of 840 EVO's waiting for this Samsung 3D flash in an m.2 form factor with a PCIe x4 with NVMe controller. All of this technology is mature, and my motherboard has the m.2 slot and BIOS support for NVMe, but Samsung hasn't put it all together yet. I'm not shelling out any more money for SATA III SSDs when I feel that any time now...Samsung will introduce the product I've been hoping for. Am I foolish to think this product in imminent? Reply
  • Impulses - Thursday, July 23, 2015 - link

    Hmm, I'm not sure anyone could really say... It's plausible they might skip retail availability of the SM951 AHCI & NVMe versions altogether and release something with 3D NAND this year, but I think they haven't released the former to begin with because the demand just isn't there outside of OEMs.

    Might change after Skylake, might not, I doubt the average enthusiast is chomping at the bit to pay $1/GB for a drive but I dunno how much cheaper the SM951 would be in volume. I'm just aiming for a 256GB SM951 post-Skylake, for the OS, paired with 850 EVOs for storage.

Log in

Don't have an account? Sign up now