[MaXimus666]

Quote:

Originally Posted by ursine

Hi, I have a three weeks old Samsung EVO 840 500GB that has the notorious bug. Read speed has dropped to 58MB/s for the three weeks old files using HD Tune Pro (see the attached three benchmark comparisons). I want to replace the Samsung EVO by Scandisk Extreme Pro.Then I had the following chain of misfortunate:

1. I cloned EVO 840 to a new Scandisk Extreme Pro using Macruim Reflect. Everything seems fine except the read speed of Scandisk Extreme Pro was about 375Mb/s much slower than the advertised 500Mb/s mark. So I tried to secure erase it and do a clean install. Acronis indicated that over 3 hours was needed to complete secure erase and I didn't want to wait and cancelled it in the middle of process. Then I did a quick format instead and the Scandisk Extreme Pro was "bricked" suddenly. The PC cannot see it with my USB-SATA adaptor.

2. Next I bought a new Crucial M500 240GB. This time I used Acronis to clone the EVO. Again the HD Tune benchmark of the cloned M500 is very poor, at 150MB/s , slower than my Seagate mechanical hard drive.

3. I did a quick format of the M500 and installed window 8 from fresh. The HD Tune benchmark of clean installed SSD is as bad as the cloned SSD. So the poor performance is nothing to do with cloning.

My system is Asus Hero VII 4790K GTX 970 16GB RAM. There are 8 x 6GB/s SATA ports. I tried manual trim but it makes no difference.

I do not understand why both Scandisk Extreme Pro and Crucial M500 are so both slow on my system. I am completely puzzled. Any advice would be appreciated. My last option is not to replace the EvO and wait for the Firmware update on the 15th .

Firstly, it is not ScanDisk, it's SANDISK!

 

[jlopz]

And other test, this seen to be ok. I think that is the same problema that:
http://www.overclock.net/t/1518996/crucial-m500-poor-performance-similar-symptoms-to-840-evo/10#post_23528533

Any ideas of why?

 

[Haswelled]

Quote:

Originally Posted by ursine

Then I have no clue how I physically killed a SSD by interrupting a secure erase and tried to quick format it. The SSD was completely dead but very warm while it was connected to a SATA USB adaptor.

The HD Tune benchmark of the Crucial M500 seems to inherit the performance degradation of the Samsung EVO after cloning. Quick format does not remove the crap in M500 inherited from the Samsung EVO bug. While the benchmark of the Sandisk Extreme Pro remains very flat and consistent, it also suffered from performance degradation in the cloning process. The more I think about, the less it makes sense. It remains a mystery until Samsung is open about the root of the problem.

Are you guys running these drives through a USB adapter cable? That will screw things up for sure and account for why you bricked the Sandisk and the slower speed readings. Are you using the same SATA port on your MB when comparing these drives to each other? Maybe you have a bad port or bad SATA cable. Ultisym is right about it being hard to troubleshoot things over the internet. When you are troubleshooting problems, try to change only one thing at a time.

 

[jlopz]

well. i think that it is better to close the question. Problem seems to be related to how HD Tune or HDtach works in SDD. In the crucial forum I have read the following:
"HD Tune is a HardDiskUtility and not suitable for Flash Memory, as it just reads LBAs without knowing if there is any date written to. If not, there is no Flash Adress mapped to the LBA and the controller does not read aynthnig for the NAND but just returns Zeros. See here: http://www.behardware.com/articles/860-4/ssd-2012-roundup-sixteen-120-and-128-gb-sata-6g-ssds.html
Another thinng is, that HD Tune with standard settings only reads 64kB every 8MB, that is why most SSDs have rather slow Read Rates with HD Tune, as 64k is just not enough to reach full seq. transfer rates. Uss CrystalDiskMark oder AS-SSD with SSD, as this benchmarks first write data to the drive and read them back later."

 

[Darkhaze]

It's probably got alot to do with whatever samsung has done to bolster it's evo and the fact that you keep cloning it. I don't care that it takes forever to rebuild my boot drives, I'm not cloning my samsungs, just keeping the important docs.

Every drive has proprietary software for secure erase, and it's usually a few seconds.

Don't you have an extra sata and power cable inside your rig or are you using a laptop?

Anyways, I've used western digital's lifeguard diagnostics program (for HDDs) to write zero's to the whole drive, it does take like while, but at least when I quick format it after that I don't worry about lingering data. And while it's a full drive worth of writes, i found it to be totally worth it. There are also 3rd party ssd utilities out there that can force trim on click, also just a few seconds for the operation.

If the sandisk still not recognized when you put it inside your computer, chances are that WD's tool will still see it, even thru USB (but don't do that man, not for serious operations), and allow you to perform the zero write. I know I've had to "unbrick" drives that way.