Tightening Ram Timings

[LIVAN]

I am currently running 2.5-4-4-9, I am trying to tighten the timings. Which should I start with first?

Thanks in advance.

 

[THUGSROOK]

2.5-4-3-9

 

[LIVAN]

So that is the RAs to cas? or the Memory switch?

 

[THUGSROOK]

ras precharge (according to cpuz)