2.6 sounds pretty fast, has it been overclocked? If so you could try turning the clock down a bit.
One way of increasing the clock speed on these is to rub a pencil on the side of one of the resistors so maybe rub some off?
I dont know what its called but I saw a video on Youtube of some guy doing it if you want to know which resistor.
good point id try rubbing it all off and leave it a default setting to see if its just to overclocked. might also need a fan pointing on it as it might be over heating.
if your in the UK or EU id be tempted to buy it off you