I recently destroyed the hard disk in my new laptop by dropping a guitar capo onto its keyboard during a filk circle. The capo landed on the K key which is more or less right exactly atop the hard disk. Though the computer is protected against gravity drops, that same sensor doesn't help if you directly thwack the disk while it's actively reading or writing data. The head crash was so bad that the BIOS refused to even recognize there was a disk drive present at all, let alone be able to boot it or recover data off of it.

Luckily, I'm religious about backups, and lost only a tiny bit of unimportant work. All my important data was already backed up in multiple locations. But I decided that I wanted to avoid the problem ever happening again. Though I had the option of calling in a replacement Winchester disk on my Sony service plan, instead I just bought a Samsung 840 EVO solid state drive to replace it, so I can feel safer about taking this laptop on the road with me. Works like a charm, I'm very happy with it so far.

I just got done rebuilding the system and getting all my apps and data back to where they belong, and then happened to stumble upon a tech article that mentioned the very disk drive I'd bought. I just went through the relatively painless "fix" process, and I thought there might be some folks here who might have the same disk drive might not have been as lucky as I to have stumbled across the article. So here's the details:

Some folks on the internet had been noticing that the performance of their 840 EVO's started to tank after they'd been up and running for a while. Turns out it's a bug in their firmware which took them a while to address. The bug caused the read performance to tank on old data blocks which hadn't been written in a while.

Samsung has released a utility to fix the issue. Alas it's Windows-only, but they say they'll have a Mac version at the end of October.

To get the fix, click here and look for 'Samsung Performance Restoration'. Run that. You can deinstall it when you're done running it.

That will both update the firmware to so that the problem doesn't continue, and also rewrite all the disk sectors so that if some of the sectors were already problematic due to age, it would fix them too.

One note about this update: The "Samsung Magician" software doesn't know about this update yet. The update puts in a new firmware version, EXT0CB6Q. Prior to running the update, if you happened to have the "Samsung Magician" software installed and you used it to check for new firmware, it would have told you the firmware was fine and was up to date, despite the fact that there's this new update available. That's what it did to me. I suppose they'll need to update the magician too, now, or something. Odd that it didn't know about this update. Not sure why.

Have fun!

I already read about that somewhere else, but thanks for reminding me to actually take the time to run that update. It took more than 2 hours for me before it was completed (my disk was nearly full AND you need about 10% free disk space or it won't work!), but apart from that everything went very smoothly and the disk indeed feels a lot faster again. This is truly a mandatory update for every Samsung EVO owner!

Do the update, it'll make you happy!

It would explain why the 512GB 840 in my MBP is running like crap. Although I'm about to swap it out for 1TB model.

What a pain in the butt.

Have an EVO 840 mSATA in my laptop and regular SATA one in a server, both of which run Linux. Guess I will keep an eye out for the DOS Bootable version which they promise to release in the next week or so.

Thanks for the heads up.

Odds are that when you get the 1TB drive, you'll still need to do this to it, since it's a firmware issue and the drives on store shelves will have the old firmware.

Other occasional Mac users might appreciate this Determine the Manufacturer of Your Macs SSD (Hard Drive).

Mine says "APPLE SSD SD256E", which is apparently SanDisk, so I'm not affected.

Hm. Original rMBP 15"'s 512gb is a Samsung. Guess I'm waiting for that update.

The update is only for the 840-EVO line, so be sure. Even regular 840's and 840-PRO's don't get this update (I think).

So the 830 series is not affected? I have one in my Mac Mini (can't say I have noticed any issues).

I don't think the 830 series is affected, the articles I read only talked about the 840 EVO line. Doesn't mean the 830 series doesn't have its own issues, but the firmware fix that I read about was narrowly targeted to the 840 EVO.

But I haven't been looking at that information for a couple of weeks, so there could be updates, or info I have missed. So if you're concerned then do some googling and see if you can find out anything definitive.

Heads up Mac & Linux 840 EVO users, the bootable firmware update is now available at the original link that Tony posted (here).

830 is not affected. I certainly notice mine seems to slow down a bit when down to the last 10GB or so (256GB drive).

I'm guessing the problem's got something to do with the 840 using TLC memory, while all other Samsung SSD's use either SLC or MLC memory.

Surprise! The 840 EVO issue isn't done with yet.

Apparently the last fix wasn't 100 percent, and there will be another fix later this month.

No, it isn't settled, annoyingly.

I have an 840 EVO, of course...

When I found out about the firmware issue I tested the drive and found that some static files had dropped to 100kbit/s rates. I've had floppy drives that were faster. I'd noticed that the machine was taking longer and longer to boot and this explained it nicely.

I did the firmware update, backed the thing up, and ran the fix tool, which restored the speed quite nicely. That was about three months ago, or so. A few days back, out of curiosity, I measured the speed again. It had dropped in exactly the same places to about 50MB/s, nowhere near as bad, but much slower than the 450MB/s+ speeds I get for most of the drive.

I ended up backing up again, rebooting in linux, zeroing the drive with dd, then putting everything bak, which got it running like the clappers again. Whether it will stay there is anyone's guess, though.

If the drive hadn't been free I'd be quite annoyed...

pca

Don't do that! It buys nothing, and wastes an erase-write cycle on the flash to no avail.

Instead, just tell the drive to self-manage the flash from scratch:

hdparm --security-set-pass NULL /dev/sdX
hdparm --security-erase NULL /dev/sdX

Much faster (like, a second or five for the entire drive), and tells the firmware that nothing on the drive needs preserving.

-ml

The new Samsung Magician software, v 4.6 for Windows, mentioned in the article, is now live at the Samsung downloads page.

There is no corresponding standalone firmware update for the drive on that page yet. If I recall correctly, that's what happened last time: the Magician software would upgrade your drive firmware and do the performance restoration, but the standalone firmware update, and the updates for other operating systems, came later.

Yeah, the Samsung Magician had a "Firmware Update" section which let me upgrade the drive from EXT0CB6Q to EXT0DB6Q firware. But neither of those are on the web site as separate firmware downloads, I think the web site is still at BB6Q.

In case anyone is reading this with a mSATA 840 EVO, Samsung Magician 4.6 for Windows still thinks that EXT42B6Q from November is the latest.

Probably have to wait a little longer.

Web Site now updated to include Mac and Windows versions of the DB6Q firmware. Anandtech reports on it here.

Does this impact the 850 Pro?

No, only the 840.

Thanks! Now to see if my boss will spring for the 256gb - I think I can live within a 256gb, and the US price is sub $200.

HOLY CRAP!

So my new work laptop arrived in, Dell E5450, with the 850 Pro SSD, and finally I'm no longer being hamstrung by all the cr@p that Corp IT run in the background.

I'll be looking out for a small SSD for the desktop at home which came with a 2TB HDD that we barely use.