Is there a problem disable these things in "Device Manager" ?

What are they used for? Is it safe to disable these in "Device Manager" ?

* High precision event timer (if you don't use it, if it is disabled in BIOS)
* Programmable interrupt controller
* System timer
Link for tutorial: Ultimate Windows 7 (8) OS gaming optimization guide (advanced but simple)

System Devices: (ONLY FOR SOME AMD SYSTEMS)
Under "Control Panel\All Control Panel Items\System" (or right click on Computer, select Properties), go to the "Device Manager" then expand "System devices". Depending on hardware configuration this can be very helpful to get constant latency and perfect smooth gameplay. Devices that should be disabled (if something goes wrong hit F8 at windows boot, select "Last known good configuration").
DISABLED (select View, click "Show hidden devices"):
* High precision event timer (if you don't use it, if it is disabled in BIOS)
* Programmable interrupt controller
* System timer
For some systems, HPET do not have any influence, however, on some systems when HPET is disabled, it is better, test it.