-snip-
start %USERPROFILE%\Desktop\VanitySearch.exe -c -o output.txt 1*
Why is it only doing 600 adresses /sec instead of 21000 per /sec as it used?
If it's not a hardware issue, my guess is: Vanityseach might be struggling to write on that output file due to its current size.
Have you been using the same 'output.txt' file since the start?
If yes, try to use a new text file like "
-o output2.txt" and see if it will speed-up.