The achievable frequency and timings depend also on the individual Cpu
you have, and on the Northbridge with older Cpu.
To test stability, I wouldn't use any software within Windows, as hardware crashes may damage any installed software. Try these:http://www.memtest.orghttp://oca.microsoft.com/en/windiag.asp
(a bit faster)
Even within Windows, Everest is no heavy load and will let you use unsafe settings. Prefer iBurnTesthttp://www.ultimate-filez.com/?page=downloads
On my Core 2 duo with P45, Ram timings have very little effect
(frequency has more) in Everest nor in more general software like SuperPi or 7zip. Does this hold for a Core i7?