try lowering your core speed and maybe you can bump the ram more? as the ram is what gives you the performance increase. mine runs at 235/395 with ramsinks 215/375 without but since one fell off(cheap fragtape....) i'm back to 215/375. usign the stock cooler with arctic silver underneath it
I got a Hercules Geforce 2 GTS 32mb OEM when they first came out and it will run at 215/375 if I recall. My new Gainward Geforce 2 Ultra/500 64mb is running at 280/510. I have not pushed it any further than that, but it's perfectly stable at that clocking.
try using a blue orb HSF and powerstrip 3.
ramsinks are deffo the way to go by the looks of things.
i would prolly chop up a copper cpu sink with me dremel rather than buy ramsinks.
to apply a ram sink use arctic silver compound and epoxy with hardener...1 part hardener to 1 part epoxy to 1 part compound.
you should think about modding your case to accomodate a fan in the side, directly over the card.
experiment with detonators too. some early versions may be better for your card than the latest version.