As you know DevTeam or Nate Jailbreak/Soft Update 1.1.3 doesn't change anything related to Hardware, the Memory/CPU speed included.
So if you update from:
- 1.1.1 > your iPhone will still run at 100/400Mhz on 1.1.3.
- 1.1.2 > your iPhone will still run at 103/412Mhz on 1.1.3.
Just to let you know guys. ;)