Weird problem with Samsung SSD 850 EVO 250GB

[Anchundan]

I actually have two of these. On one I installed Windows 7, and the other Windows 10. I haven't had to use Windows 7 much, as nearly 100% of my software is compatible with Windows 10.

The problem I have had is, as soon as I get into Windows 10 and open up Windows Explorer, it takes a huge amount of time to display all the files in a folder. It doesn't matter whether it's on an external drive or the system folder, it takes many minutes until I can see everything. Windows 7 (on the other SSD) doesn't have this problem at all.

So over Christmas I formatted and re-installed Windows 10. But I still have the same problem.

In the end, I formatted Windows 7, and installed Windows 10 on that drive, and the problem is cured! So now I have a slow running Windows 10 on Disk 0 SSD, and a fast running Windows 10 on Disk 1 SSD.

So I suspect I have something wrong with the slow SSD. I open Samsung Magician, both are running the same (latest) firmware. Both are showing 'Good' drive condition. In performance benchmark, I get the following:

Win10 Fast:
Sequential Read (MB/s): 549
Sequential Write (MB/s): 491
Random Read (IOPS): 88,098
Random Write (IOPS): 68,224

Win10 Slow:
Sequential Read (MB/s): 552
Sequential Write (MB/s): 530
Random Read (IOPS): 91,023
Random Write (IOPS): 73,526

so the slow drive should actually be performing better than the fast one!!!

The last strange thing I noticed was the Total Bytes Written:

Win10 Fast: 0.7TB
Win10 Slow: 7.2TB

I bought both drives at the same time, end of July 2015.

Any ideas how to explain this? Or how to fix it?

 

[Anchundan]

bare windows 10 install, I reinstalled purely to speed things up, so it was the first thing I checked. I'm wondering whether it's anything to do with the sata port that it's plugged into? I have the Asus Z97 Sabretooth Mark S motherboard, but I don't really know what I'm talking about!

 

[Anchundan]

I've been down with flu for the last week, but just tried plugging the slow drive into the slot right next door to the fast drive, which is in an ASMedia Serial ATA 6.0Gb/s slot (it was in an Intel Z97 Serial ATA 6.0Gb/s slot).

Unfortunately, the performance is exactly as it was, taking ages to show contents of any large folder. So I don't know what else there is to do? tried reformatting and reinstalling windows. Tried a different SATA slot on the motherboard (albeit without reinstalling Windows 10), and still the same issue. It does have a 5 year warranty, but according the Samsung Magician, the drive condition is 'Good', and the performance benchmark shows that. It's just real-life usage that shows that everything is far from ok. Do I have a chance by sending it back?

Actually, I just re-ran the performance benchmark and now get (Win10 Slow):
Sequential Read (MB/s): 400
Sequential Write (MB/s): 375
Random Read (IOPS): 47,595
Random Write (IOPS): 27,606

so it is finally accepting that it's underperforming. Still don't know what I should do though!

 

[Anchundan]

sounds like a plan

 

[Anchundan]

...and the plan worked! secure erased that drive (eventually, after I realised why I couldn't boot from the bootable USB Magician created), reinstalled Win10, and the speed is back up again, no delays when opening large folders.