I have a Windows 7 Pro HP z200 system with an MTFDBAK256MAG-1G1 (Micron RealSSD C300 240 GB). I notice that the drive's performance is fine when the disk is booted, then during the course of a Windows session the read performance drops to 1/10 of it was at the start!
And, rebooting returns the SSD to its original speed. In/out of sleep mode does not have the same effect. I've tried all the standard tweaks after installing the SSD into a computer (Registry settings, superfetch disabled, etc.).
The disk is about three years old; I actually had it in my laptop but moved it to this desktop, replacing a SATA HDD. Is this a characteristic of an SSD getting old? Are there diagnostic utilities that can tell if there is something going wrong with the disk? I have Intel Rapid Storage Technology installed and it says everything is fine, as does sfc and chkdsk.
Below are some specific data points that may further explain what I'm seeing. I don't have any tests that could be replicated here; perhaps someone knows of a continuous output read tester?
One way I can tell is, I have a script which I call from a command line. It allows me to do regex searches on a recursive/ wildcard set of text files; a small perl script is called for each file that does the regex search. I have a little status indicator that increments a counter for each file processed.
In a directory with 200 text files, none over 70kB, the script starts processing about 20 files/sec. After about 50 files, the speed visibly drops until near the end of the processing, the script is processing TWO files/sec. Worse, once this happens, running the script over the same set of files with the same criterion, or over any set of files with different criterion, the performance is now the same!
I know it's not just the script, because once this happens, starting a new program, or closing an existing program, takes several seconds.
Final data points: on my colleague's machine, which has a Kingston SV300 100 GB SSD drive, the same script over the same 200 files with the same criterion never wavers from the ~20 files/sec benchmark. This can be repeated many many times with no slowdown. And the consistent rate on my laptop with its old SATA HDD is 10 files/sec.