Samsung SSD 840 EVO Review: 120GB, 250GB, 500GB, 750GB & 1TB Models Tested
by Anand Lal Shimpi on July 25, 2013 1:53 PM EST- Posted in
- Storage
- SSDs
- Samsung
- TLC
- Samsung SSD 840
Inside the Drives & Spare Area
The EVO is offered in a single form factor - 2.5" at a 7mm thickness. There are three torx (T5) screws that hold the chassis together, removing them gets you a look at the EVO's very simple internals. Surprisingly enough there's no thermal pad between Samsung's MEX controller and the chassis.
Samsung, like Intel, does a great job of reducing the number of screws and simplifying the assembly of its drives. I would prefer if Samsung didn't insist on using torx screws to hold the chassis together but I'm sure it does have some impact on reducing returns. There's also growing concern of counterfit SSDs which I guess screw choice could somewhat address.
There are two PCB sizes used in the EVO lineup, neither of which occupies the full volume of the 2.5"/7mm chassis. The 120 and 250GB drives use the smallest PCB, while the other drives use the larger layout. The larger PCB has room for 8 NAND packages, while the half length PCB can accommodate two. Each of the NAND packages can hold up to 8 x 128Gbit 19nm TLC die.
To deal with the realities of TLC, Samsung sets aside more of the drive for use as spare area on the EVO than it does on its MLC Pro line. Due to TurboWrite however, the percentage is actually a bit less than it was on last year's 840.
| Samsung SSD 840 EVO Memory | |||||||
| Advertised Capacity | 120GB | 250GB | 500GB | 750GB | 1TB | ||
| DRAM Size | 256MB LPDDR2-1066 | 512MB LPDDR2-1066 | 512MB LPDDR2-1066 | 1GB LPDDR2-1066 | 1GB LPDDR2-1066 | ||
| # of NAND Packages | 2 | 2 | 4 | 8 | 8 | ||
| # of NAND die per Package | 4 | 8 | 8 | 4 | 8 | ||
| NAND Capacity per Package | 64 GiB | 128 GiB | 128 GiB | 96 GiB | 128 GiB | ||
| Total NAND | 128 GiB | 256 GiB | 512 GiB | 768 GiB | 1024 GiB | ||
| Spare Area | 12.7% | 9.05% | 9.05% | 9.05% | 9.05% | ||
I've tossed internal shots of all of the EVO lineup into the gallery below:
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yut345 - Thursday, December 12, 2013 - link
That would depend on how large your files are and how much space of the drive you will be using up for storage. I would fill up a 250GB drive almost immediately and certainly slow it down, even though I store most of my files on an external drive. For me, a 1TB would perform better.Romberry - Saturday, July 27, 2013 - link
Well...that sort of depends, doesn't it? The first 2.5-3GB or so are at close to 400mb/s before depleting the turbowrite buffer and dropping down to around 110-120mb/s, 2-3GB covers a lot of average files. Even a relatively small video fits. And as soon as the turbowrite cache is flushed, you can burst again. All in all, long (very large file) steady state transfer on the 120gb version is average, but more typical small and mid file sizes (below the 3GB turbowrite limit) relatively scream. Seems to me that real world performance is going to be a lot quicker feeling than those large file steady state numbers might suggest. The 120gb version won't be the first pick for ginormous video and graphics file work, but outside of that....3GB will fit a LOT of stuff.MrSpadge - Saturday, July 27, 2013 - link
Agreed! And if your're blowing past the 3 GB cache you'll need some other SSD or RAID to actually supply your data any faster than the 128 GB 840 Evo can write. Not even GBit LAN can do this.nathanddrews - Thursday, July 25, 2013 - link
RAPID seems intended for devices with built-in UPS - notebooks and tablets. Likewise, I wouldn't use it on my desktop without a UPS. Seems wicked cool, though.ItsMrNick - Thursday, July 25, 2013 - link
I don't know if I'm as extreme as you. The fact is your O/S already keeps some unflushed data in RAM anyways - often times "some" means "a lot". If RAPID obeys flush commands from the O/S (and from Anand's article, it seems that it does) then the chances of data corruption should be minimal - and no different than the chances of data corruption without RAPID.Sivar - Thursday, July 25, 2013 - link
You can always mount your drives in synchronous mode and avoid any caching of data in RAM.I wouldn't, though. :)
nathanddrews - Thursday, July 25, 2013 - link
soo00 XTr3M3!!1 Sorry, I just found that humorous. I've actually been meaning to get a UPS for my main rig anyway, it never hurts.MrSpadge - Saturday, July 27, 2013 - link
It does hurt your purse, though.sheh - Thursday, July 25, 2013 - link
I wonder how it's any different from the OS caching. Seemingly, that's something that the OS should do the best it can, regardless of which drive it writes to, and with configurability to let the user choose the right balance between quick/unreliable and slower/reliable.Death666Angel - Friday, July 26, 2013 - link
That was my thought as well. The OS should know what files it uses most and what to cache in RAM. Many people always try to have the most free RAM possible, I'd rather have most of my RAM used as a cache.