I use the below as startup options on Dayz SA
-nosplash -noPause -cpuCount=8 -maxMem =8192 -high -nologs
Obviously your CPU count will need to be 4 and maxmem a useable figure (depending on you ram)
But try that and see where you go, I tend to get a fairly decent 60fps in Dayz now with the odd dip to 40.
-nologs makes a good difference IMHO
I had a problem with games stuttering, i had an SSD drive for a while and since getting that i forget to defrag my mechanical drive with all my games on, since windows allway so quick with the SSD. Since i dont know ur spec , i guess you could need to defrag drive if it mechanical.