Review Index:

Samsung 840 EVO 500GB and 1TB Full Review - TurboWrite TLC

Subject: Storage
Manufacturer: Samsung

IOMeter v2006.07.27 - IOps

Iometer is an I/O subsystem measurement and characterization tool for single and clustered systems. It was originally developed by the Intel Corporation and announced at the Intel Developers Forum (IDF) on February 17, 1998 - since then it got wide spread within the industry.

Meanwhile Intel has discontinued to work on Iometer and it was given to the Open Source Development Lab (OSDL). In November 2001, a project was registered at and an initial drop was provided. Since the relaunch in February 2003, the project is driven by an international group of individuals who are continuesly improving, porting and extend the product.

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Light desktop usage sees QD figures between 1 and 4. Heavy / power user loads run at 8 and higher. Most SSD's are not capable of effectively handling anything higher than QD=32, which explains the plateaus.

Regarding why we use this test as opposed to single-tasker tests like 4KB random reads or 4KB random writes, well, computers are just not single taskers. Writes take place at the same time as reads. We call this mixed-mode testing, and while a given SSD comes with side-of-box specs that boast what it can do while being a uni-tasker, the tests above tend to paint a very different picture.

I've altered the presentation of these charts slightly as compared to the norm. They are usually in alphapetical order. This time I've arranged them in the order in which they are run. We run the series back-to-back, which gives the drives no time to catch their breath. This is normally not an issue, but in the case of caching SSDs, the SSD with the smaller cache has a greater chance of filling it. In this case, the 500GB EVO performs right up there with its 1TB brother right up until the point where the cache becomes full. Since this is a mixed workload test, it had the unfortunate side effect of tricking the 500GB model into attempting to write its cache to TLC while writes were still being requested of the drive itself. This resulted in overall speeds dropping to below that of the older TLC-only 840. I suspect this was due to the mixed and random workload combined with the cache overhead simply overtaxing the controller, resulting in a dip in random read IOPS, which ultimately held back overall IOPS.

Keep in mind this is not exactly a consumer oriented test. It's rare that any non-enterprise user is actually going to put an 840 EVO through this type of torture. Not for as long of a period as we do, anyway.

July 25, 2013 | 09:34 AM - Posted by Mark Strong (not verified)

Thank you for the quick review sir. Personally I would call this a no question automatic upgrade for a new PC build. I'm interested to hear your thoughts on where this stacks up in the grand scheme of things.

July 25, 2013 | 10:02 AM - Posted by Allyn Malventano

If the pricing holds (and that's a big IF since I have yet to see sub-$1/GB pricing hold), the EVO will become my default recommendation for everything but the most demanding enterprise use.

July 25, 2013 | 10:38 AM - Posted by Mark Strong (not verified)

Then let us hope with fingers crossed that the price roughly holds (within 10 - 20 dollars). Much appreciated sir.

July 25, 2013 | 11:14 AM - Posted by grommet

I didn't see in the article when these would be available- did I miss it, or are they not saying yet?

August 12, 2013 | 12:52 AM - Posted by Allyn Malventano

No hard date, but I'd imagine as quickly as they can get them out there.

July 25, 2013 | 12:44 PM - Posted by Thedarklord

Great review.

As someone who is about to jump onto the SSD train;

1)It looks like several SSD makers are releasing new products now/very soon (so is it better to wait?)

2)I personally like the Corsair lineup, anyone heard anything if they are exiting the market?, seems like their SSD market is getting scarce.

, Thanks

July 25, 2013 | 01:30 PM - Posted by Ram Rangaswamy (not verified)

Allyn Malventano: The last line of the article says "...Samsung 840 ECO..." instead of EVO.

Otherwise, love the article and insight!

July 25, 2013 | 06:01 PM - Posted by Tad (not verified)

LOL PCMO5? What the hell? and Iometer 2006? ROFLSAUCE! Its like I ran into an '80's website. Does your SSD wear parachute pants too?

July 26, 2013 | 01:23 PM - Posted by Photonboy (not verified)

If a tool works to accurately assess a product, why does it have to be made very recently?

An older product is also well understood and allows accurate comparisons to previous products that also tested with the same tools.

August 12, 2013 | 12:50 AM - Posted by Allyn Malventano

^ this.

July 29, 2013 | 11:54 AM - Posted by Moochacho (not verified)

Is there any benefit these days (performance or stability) to having one SSD for OS, another for programs and a third for data? Back in the day I used to have the OS on its own partition or even different drive, so it wouldn't get all fragged up. I currently have a 120GB OCZ Vertex3 for OS, 1TB Samsung Spinpoint for progs and 500GB WD Black for data and trying to eliminate spinning drives for new build.

July 30, 2013 | 11:06 PM - Posted by irdmoose

Hey Allyn, thanks for the great review. It looks like the bug you caught to get this review out may have been worth it, and I hope that you get well soon! How well do you think these drives will perform in a RAID-0 setup with say an Intel controller on either Ivybridge or Haswell systems?

August 12, 2013 | 12:50 AM - Posted by Allyn Malventano

They should be just fine, so long as the partition is correctly aligned (not an issue for Vista and newer). There may be a slight performance hit due to TRIM not passing through to a RAID-0 (which is still a mixed bag as far as it actually working), but it should be minimal impact for regular usage.

August 13, 2013 | 03:08 PM - Posted by jgstew

I think in the case of workloads with very little writing like a file server, the 840 EVO and similar SSDs could be an interesting replacement for something like this:

With a significantly lower $/GB and better read performance.

August 23, 2013 | 05:38 PM - Posted by klatch

Is there a concern that the flash in the turbowrite buffer is going to die early? or does it get load balanced around the drive? I was sort of expecting the buffer to actually be SLC, but if it is just making TLC operate as SLC is that functionally equivalent to it being SLC?

September 17, 2014 | 10:45 PM - Posted by Grand Nagus (not verified)

Allyn Malventano

What is the update on the 840 EVO problems?


If they don't fix the problem you should downgrade the review to Bronze or worse. :)

I bought this drive on PCPERs recommendation and now I'm pissed.

December 25, 2014 | 10:54 PM - Posted by Obat Kanker Vulva Herbal (not verified)

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