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I have a couple of Samsung 840 EVOs that are slowing down again. Samsung has promised a fix, but in the meantime I just ran Spinrite Level 3 on them and restored them to full performance.

HOWEVER, this is not a problem just with 840 EVOs. I am noticing that all MLC SSDs start slowing down gradually over time (which is why from now on I'm going to buy pricier SLC drives). I have a Kington SSD I use as a boot drive on my gaming PC and two Samsung 840s on my main workstation (non-EVOs which are not supposed to suffer from the EVO problem). All three have slowed down. One of the 840s quite dramatically.

Spinrite Level 3 (which reads the sector and writes it once) refreshed them all and brought them up to full performance. If you're not a Spinrite owner, the other trick that people are using that works pretty well is to download a free Defrag program called MyDefrag: http://www.mydefrag.com/Manual-DownloadAndInstall.html

I recommend unchecking the "Install scheduled tasks" option in the installer.

And then run one particular defrag script called "Data Disk Monthly" that moves every single sector on the drive (except for unmovable sectors) which essentially every sector to be read and re-written. I actually ran that on my laptop with an 840 EVO and it did also bring it back up to full performance. Running Spinrite on level 3 is a bit more efficient though.

As an example, here's the Samsung 840 boot drive off my main workstation, which was getting noticeably slow when I had to reboot it last week for a Windows Update (remember, this is a non-EVO drive so it's not supposed to be affected by the known slow down issue, yet performance was pretty awful):



and here it is after I ran Spinrite 3 on i (I'm maxing out at 166 MB/s because this is an older mobo that doesn't have SATA 3 ports):



So it's looking like a bi-annual Spinrite Level 3 scan is a good thing for SSDs.

Interesting.

I am noticing that all MLC SSDs start slowing down gradually over time (which is why from now on I'm going to buy pricier SLC drives)

How can you tell when ordering SSD to buy the SLC type? I've bought about 3 of them in the last year, but always went with price first.

It's clearly noted in the specs usually. SLC is normally found in workstation/server grade SSDs. They cost more because each cell represents one bit. In MLC drives each cell can represent two bits (doubling the storage), however the tradeoff is a slight performance hit and less reliability. MLC drives require more aggressive error correction.

http://en.m.wikipedia.org/wiki/Multi-level_cell

I don't think I ever used option #3 of SpinRite. Also, didn't Gibson say he was going to come out with an updated version of SpinRite?

Option 3 is rarely used on a spinning drive. It's meant to be less aggressive than 4 if the drive is near it's last legs.

Option 3 reads once and writes once, every sector. Option 4 reads a sector inverts the bits, writes it, reads it again, inverts the bits and writes it again (2 reads, 2 writes each sector).

Option 4 is a waste of an extra write cycle on SSDs.

Yeah, after Steve finishes SQRL (very close to done) he's going back to finishing Spinrite 6.1 (free upgrade) and eventually Spinrite 7.

6.1 will abandon DOS an be able to run on systems with UEFI Bioses (like Macs and most Win8 PCs), and also will access Sata ports at full bandwidth. It will run much faster than 6.0.