I have a 256gb samsung ssd in my M11X. When I first got the computer I benched it using crystal disk mark. The write speeds were 90MB/s ish. 18 months later the write speed has gone down to 23MB/s. The read speed has stayed pretty much the same. I have reinstalled windows twice since new.
How can I restore my ssd back to peak performance? I read somewhere that if I erase the disk completely, ie write over all the data with 0's I will restore my write speed.
Write over all the data with zeros will make things worse. The issue is that the drive keeps a list of which cells are used, and it doesn't know about deleted files (or abandoned copies of the OS) unless the TRIM command names the specific sectors being made unused.
1) Some people say that Garbage Collection can deal with this. Leave your machine switched on but idle overnight.
2) Do a factory reset with the Secure Erase command and re-install. You can do a Secure Erase with the bootable Parted Magic cd, among many other utilities.
3) Write a huge file that takes up all your freespace. Delete it. Win7 will then tell the drive that all of those sectors are unused. Very few people believe that this works.
4) If such a thing exists, run a utility that sends the TRIM command for all free sectors on your partition.
Are you running Win7? Is the chipset drive controller set to AHCI mode instead of legacy IDE mode? Have you checked for 4K block alignment? These may be important to SSD performance.
Finally, was that 90 MB/s the serial write rate, or random? Seems a bit slow for serial.