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