The Samsung SSD 850 EVO mSATA/M.2 Review

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Four months ago Samsung introduced the world to TLC V-NAND in the form of SSD 850 EVO. It did well in our tests and showed that 3D NAND technology essentially brings TLC NAND to the level where planar MLC NAND stands today. The initial launch only included the most popular form factor in 2.5", but did not address the upgrade market where mSATA and M.2 are constantly growing in popularity. With today's release, Samsung is expanding the 850 EVO lineup with M.2 and mSATA models.

The move isn't really surprising because Samsung released an mSATA version of the SSD 840 EVO a bit over a year ago and when the 850 EVO was originally launched we were told that mSATA and M.2 models would follow later. The addition of M.2 is new to Samsung's retail lineup, but it makes a lot of sense given that many PC OEMs have switched from mSATA to M.2, and ultimately M.2 will be replacing mSATA in full.

Architecturally the mSATA and M.2 models are not any different from their 2.5" sibling. The heart of the drives is still Samsung's own MGX controller (excluding the 1TB model, which is powered by the older MEX controller) and the NAND is 32-layer 128Gbit TLC (3-bit per cell) V-NAND that is manufactured using 40nm lithography. TurboWrite (Samsung's pseudo-SLC caching) is also included and the cache sizes have remained unchanged from the 2.5" model. DevSleep and TCG Opal 2.0 (eDrive) are both supported too and endurance comes in at a respectable 75TB for 120GB/250GB and 150TB for 500GB/1TB models.  

Given the similarity with the 2.5" model, I strongly suggest that you read our 850 EVO review for a full scope of TurboWrite, TLC V-NAND and other tidbits as I won't be covering those in detail in this review. 

Samsung SSD 850 EVO mSATA Specifications
Capacity 120GB 250GB 500GB 1TB
Form Factor mSATA
Controller Samsung MGX Samsung MEX
NAND Samsung 40nm 128Gbit TLC V-NAND
DRAM (LPDDR2) 512MB 1GB
Sequential Read 540MB/s 540MB/s 540MB/s 540MB/s
Sequential Write 520MB/s 520MB/s 520MB/s 520MB/s
4KB Random Read (QD1) 10K IOPS 10K IOPS 10K IOPS 10K IOPS
4KB Random Read (QD32) 95K IOPS 97K IOPS 97K IOPS 97K IOPS
4KB Random Read (QD1) 40K IOPS 40K IOPS 40K IOPS 40K IOPS
4KB Random Write (QD32) 88K IOPS 88K IOPS 88K IOPS 88K IOPS
Steady-State 4KB Random Write Performance 3.1K IOPS 4.9K IOPS 6.8K IOPS 9.7K IOPS
DevSleep Power Consumption 2mW 2mW 2mW 4mW
Slumber Power Consumption 50mW
Active Power Consumption (Read/Write) Max 3.5W / 4.3W
Encryption AES-256, TCG Opal 2.0, IEEE-1667 (eDrive)
Endurance 75TB (41GB/day) 150TB (82GB/day)
Warranty Five years

Like its predecessor, the 850 EVO mSATA offers capacity of up to 1TB, which still remains the highest capacity mSATA drive in the industry. Samsung has a substantial lead in its NAND packaging technology because currently no-one else is shipping 16-die packages in high volume and by comparison Samsung has been doing this for quite some time now. I've heard Toshiba has some 16-die packages available, but the yields are very low and pricing comes in at about a dollar per gigabyte, whereas other packages are priced at ~30 cents per gigabyte. Micron also has 16-die packages on paper, but I've yet to see them used in any actual products.

Samsung SSD 850 EVO M.2 Specifications
Capacity 120GB 250GB 500GB
Form Factor M.2 2280 (single-sided; SATA 6Gbps)
Controller Samsung MGX
NAND Samsung 40nm 128Gbit TLC V-NAND
DRAM (LPDDR2) 512MB
Sequential Read 540MB/s 540MB/s 540MB/s
Sequential Write 500MB/s 500MB/s 500MB/s
4KB Random Read (QD1) 10K IOPS 10K IOPS 10K IOPS
4KB Random Read (QD32) 97K IOPS 97K IOPS 97K IOPS
4KB Random Write (QD1) 40K IOPS 40K IOPS 40K IOPS
4KB Random Write (QD32) 89K IOPS 89K IOPS 89K IOPS
Steady-State 4KB Random Write Performance 2.8K IOPS 4.1K IOPS 5.8K IOPS
DevSleep Power Consumption 2mW 2mW 2mW
Slumber Power Consumption 50mW
Active Power Consumption (Read/Write) Max 2.4W / 3.5W
Encryption AES-256, TCG Opal 2.0, IEEE-1667 (eDrive)
Endurance 75TB (41GB/day) 150TB (82GB/day)
Warranty Five years

Unfortunately the M.2 version tops out at 500GB. The reason lies in the fact that the M.2 is a single-sided design, which only has room for two NAND packages. There are quite a few laptops that use the single-sided M.2 2280 form factor as it allows for thinner designs, but I still would have liked to see a 1TB double-sided version. It is worth noting that while both PCIe and SATA based devices can have M.2 form factors, Samsung is only releasing the 850 EVO M.2 in the SATA format at this time.

With a 128Gbit die and sixteen die per package, the maximum capacity for each package comes in at 256GiB, yielding a raw NAND capacity of 512GiB, of which 500GB is usable in the 850 EVO.

AnandTech 2015 SSD Test System
CPU Intel Core i7-4770K running at 3.5GHz (Turbo & EIST enabled, C-states disabled)
Motherboard ASUS Z97 Deluxe (BIOS 2205)
Chipset Intel Z97
Chipset Drivers Intel 10.0.24+ Intel RST 13.2.4.1000
Memory Corsair Vengeance DDR3-1866 2x8GB (9-10-9-27 2T)
Graphics Intel HD Graphics 4600
Graphics Drivers 15.33.8.64.3345
Desktop Resolution 1920 x 1080
OS Windows 8.1 x64