Few Quick Steps I take to speed up my personal experience.These methods are used mostly for SP by me.

OS Used:Windows XP(Hibernation enabled)

1.
#Install the game whatever it may be.
#Make a new administrative account with new name.
#Ativate Hibernation if not active.
#Log OFF & log in into the newly created account.
#Play the game & hibernate the computer after you had your you fun.
#Do not turnoff / restart /logoff that account you used.

[How it works: On first loading only 5-7 processes are loaded by defaut by the OS & all the remaining memory can be used by the game.wheras on your normal & used account one will have 27-30+ processes running]

[I have personally tried this for many games on my PC which is pretty shit.(512MB RAM nothing else)]

[Personal Exp: Both on my Laptop & PC
GTA San Andreas :
->Ran OKay with few lags at low settings,At medium settings used to run with a lot of pauses & lags.
->On trying the method I suggested it ran pretty smoothly at almost high sett & max antialias GTA supported.

I've had better experience playing NFS & FIFA too.]


The performance boost would be great for low & med end PCs & if you don't find much boost sorry , It worked for me & I play all my demanding SP games that way.
I just thought it could help someone.

If this dosen't belong here ,move the thread.