If I have correctly understood your question. We use uniq speeds of turn of towers, tanks, Prompting and aiming for ALL UNITS!
According to historical and specifications
System recommended:
PIV 3 Ghz or AMD
RAM 1Gb
Video Nvidia GF6600 or more
Sound Audigy 2 ( best sound)
HDD 3 Gb free
Minimal configuration
PIV 2. Ghz or AMD
RAM 512 Mb
Video Nvidia GF5700 or more
Sound DirectX compatible
HDD 3 Gb free