I don't recall whether the Q9650 stock heatsink had a copper slug still or not, but the Rosewill RCX-Z90 AL ($13) is pretty much an exact copy of the stock Intel HSF. You could probably get a stock Intel HSF on Ebay for cheap also.
Once you step up to the $35-$45 range, you'd be getting better cooling performance....but whether or not that extra performance is necessary or not....dunno.
I'd like to use the 4-pins for the PWM to work so it will be silent (Or I'm wrong and it can be silent even without PWM)
And, it's not that I want to avoid push pins, I just can't install push pins there because it has threads for screws (Or again I'm wrong and I can still use push pins with that? It's just an HP compact machine so maybe things are different)
**Edit: And anyway the Rosewill is designed for up to 86W tdp and won't be enough for the 95W of the C2Q
It's A custom mini heatsink for this small form factor pc. 80c is too hot because it's rated for maximum 71c. I thought about ziptying a 70mm fan to it. Do you have a recommendation for a not too loud 70x70x15mm fan? Thanks
Do you have a make/model for the pc?
Or, perhaps a photo of the space you have to work with?
Does your current cooler now have a fan attached, or is it just a heat sink?
Any cooler needs a source of fresh air to let it do it's job.
If there is no fan to help get air into where the cpu and cooler are, nothing will really help. You could limit the max performance in windows from 100% to perhaps 80% to get the heat down.
a 70mm fan needs to run at very high rpm to do any good.
There are some 80mm noctua fans tat are relatively quiet.