You say SR4. If you really mean SR4 rather than SR4.1 then you need to upgrade. SR4 was meant to speed up P5 over SR3, but for some of us (not sure of the common cause, but suspect the early release CD for P5 as it had some differences in the XML fles) SR4 was slower than SR3 and even SR2. But for me SR4.1 speeded up P5 way beyond anything in any earlier release - still slower than P4 or even ProPack, but at least usable (with CP removed of course). I don't use sub-folders, so can't confirm that aspect.