My experience with Samsung SSD

I've been using a 850 EVO for a couple of months and its been terrific.

That is the most confusing poll I've seen in a while

850 Pro, flawless so far. Been using it for half a year at this point.
knocks on wood

I have a regular 840, and it has been working great for the past 3 years.
If you haven't already, install Samsung Magician and update the firmware of your SSD. Also make sure you have at least 20% of your SSD free.

The fact that the problem goes away when you restart your PC seems to point at something else. I'd try running Memtest for safety: a faulty RAM, while rare, can lead to weird behaviors.

I haven't used any Samsung SSDs, but from what I've read, the 840 EVOs have a problem with old data. That is, data that has been on the drive for some time. It gets read very slowly. Samsung have released 2 firmware updates just for this, but I don't think it's completely fixed. What the "fix" did was to overwrite all data on the drive, so that all data is new and so the problem would go away for some time (this was after the 1st fix released). I think the 2nd did something similar, but don't remember. Still, it might be worth it to check, whether your firmware is recent. If you decide to upgrade it, back up your data first!

Forgot to say, don't use Samsung's RAPID function, it fools you into thinking your SSD is much faster, but all it does is use some of your RAM as cache and inflate your scores in synthetic benchmarks without real-world gains. It actually increases the chances of data loss, if your computer loses power, freezes or restarts unexpectedly, because then you would have more data in the RAPID RAM cache than normally and it wouldn't have been written back to the disk.

Use Samsung Magician, upgrade SSD's firmware and optimize them. I've been using EVO 840 for a year now and I get better read/write speeds than the actual number they put on ssd box.

my 840 EVO is still going strong :3

I've heard someone 850 PRO bricked after firmware upgrade, so Samsung Magician is a no no to me.

I have a 840 evo (one year old) on and i dint have any problem until now.
System starts very fast (w8.1) and no issues with files.
i recommend you to active overprovisioning and optimice your ssd with samsung magician. As other user said, dont use rapid mode.

Using 840 evo, everything working perfectly.

I used the samsung magician and firmware update when they released it and it works flawlessly (and fast!).

If the problem gets solved after a restart, maybe the one to blame is not the SSD....

had these for quite a long time:

830 64 GB x 4 - some years 3+ (OS Partition on 4 PCs)
840 128 GB x 1 - 2 years (OS Partition in a NB + hdd-drive-caddy instead dvd)

^ never had any issues with the SSDs themselves...
upgraded the firmware at least once on all SSDs

never going to buy samsung ssd again. more info here http://www.overclock.net/t/1507897/samsung-840-evo-read-speed-drops-on-old-written-data-in-the-drive

As additional information I cannot migrate from 840 EVO to 850 PRO it failed after 100% copying data.
I had to clean install the Windows because of that.

No problem so far with a 850 EVO. Runs super fast and super smooth.

I have Samsung 840 EVO 1TB about almost 2 year old. No issue at all. If you are formatting(full) these drive, which you are killing their lifespan. And it will become slow. That what I did with my old Chronos 120gb, it became slow after formatting couple time without knowing.

not using any now, but have used 840 EVO 128GB and 850 EVO 250GB and both have been as great as possible, no issues encountered

I had Stuttering on read/write with my 2 HDDs, until I fixed the cable and problem gone. bad cabling leads to problems.
let the cable free! it have a right to be free! :V

I've had 840 EVO for about half a year with no issues at all, it's honestly been one of my better purchases this year. :3

i still don' know why people use SDD...sure it's super fast.you can copy files much more quickly and run programs much more smoothly (smoothly...is that a word?) but ther are still so expensive and i think it doesn't worth the money

I have 840PRO for more than one year and there was no problems so far..

Using 840 EVO 250 GB for 18 months now no issues so far and expensive ... it depends I bought mine new for 70 $.

I've had a Samsung 840 SSD for a year and a half at least and I love it.

That's odd, they're widely regarded as the best bang for your buck SSDs.

I use a Samsung 840 non-pro and it is also affected by the slow speeds for old data. The way Samsung has handed this issue on all models and denying it exists on the non-pro models means I won't be buying a Samsung SSD again. There is a thread in the german computerbase forums that has 100s of pages.

Okay now my Samsung 850 Pro, show the second symptom, loading windows 10 very long in 10+ minutes now (I clean install Windows 10 from start - after formatting), might try those samsung magician after all.