I have a 965P-DS3 and if you are using the DS# board, you WILL need a fan on the Nrothbridge heatsink.
Even at idle it gets too hot to touch, however by putting a small fan on it, it now runs at a temperature that is much , much cooler.
Here's the heatsink standard:
And with the small fan I bought at a local PC shop:
It just screwed straight into the fins on the heatsink and on the motherboard you'll see a 3 pin plug label NB Fan right next to the Northbridge. I'm yet to shorten the fan wires to be neater, but I will get around to it.