buy the 2500 or 2800

[Satai]

I am in the process of builing a gaming computer. i was going to buy the amd 2800 but i was then told i should get the 2500. this is because it has a lot softer overclock. i am new to overclocking and i dont know much yet but i plan on doing it to my new computer. which one should i go with?
thankyou

the mobo is an A7N8X wich supports 400Mhz
1 stick of 512MB ram 400MHz