Just got an E8400 in my hands just to test...it seems more overcloackable although it's a 1333 fsb (whereas E7500 is 1066)!
With everything on Auto in Bios except Multi (9.0) and FSB at 500 I had easily 4.5ghz enjoyable!!
Same thing as with the E7500 here with this cpu started to happen at 510 x 9.0, played a little with voltages (cpu and ram) but nothing successfull!!
Waiting for your inputs