From the look of it, it seems like a northbridge heatsink should fit but per se it looks like these holes are made for small heatsinks and small fans which usually ends up producing a high pitch noise, in the past i 3d printed brackets that gave me the possibility to attach bigger fans than normal on small heatsinks, that's one solution.

There must have been someone who changend the fan/cooler on such a parhelia card....?
I am currently using a P650 that is an excellent card, but has half the bandwith and half the tmu's/shaders etc. and that cut the performance more than in half.

Just measure the hole distance and order the right type of heat-sink.

Anybody equipped a passive cooled Geforce 3 TI (which gets very hot that way) with an aftermarket cooler?