E7500 can be overclocked?? Never heard of it....!! Well.......wait for other members to reply.
^^
There is an OC thread here, I have put a detailed guide how to OC LGA775. Yes your chip will OC easy. Read that guide. Be careful.
Here you go.
How you cooling that chip....? Have you turned off all the auto management features, C1E, EIST, Speedstep..! How you got to that vCore.
You would need to pour more vCore to the core. Be really careful. Follow the guide I made. Increase in increments of 0.1v, and run stability tests, and monitor the temperatures, do not just walk away.
vCore, is the voltage which goes into the CPU. When you make it run at higher clocks, it needs more power. But you have to be extremely careful with this parameter, it can cause the chip to burn. Keep the Mx at the highest possible, for the E7500, and toggle the FSB. When you reach instability, increase the vCore a bit. But you should hit a wall, quite soon, since it is stock cooled.
How are you checking for stability..?
I think that is about it for you. With stock, 1.4v is quite a lot. Try not to push it more. Could you post a RealTEMP run here, with 2x Prime95 threads. Thanks.
You going directly to 1.4. To it in small increments (0.02v) from 1.28v onwards. SpeedFan is not reliable for temperatures. Use RealTEMP. It has a good benchmark utility.