My 8RDA is down until I can replace the RAM (it's dead, Jim) on Monday (lifetime warranty, good). I figured I might as well clean the cooler on my PNY Ti4600. I decide to lap it since the bottom of the heatsink unit doesn't look all that smooth. I didn't do much lapping, but it appears that at least part of the unit is copper. I doubt it'll give me anything extra in overclocking, as the Ti4600's were clocked pretty close to the edge at stock speeds, but the contact should be better. I don't know if this is on all Ti4600s or not, but it was on mine. Pic attached to show off.