Originally Posted by
Gautam
no IHS appeared to result in better core frequencies while the memory became pretty much un-overclockable. Actually did a test one step further with an IHS and a shim on top of the IHS, and I ended up getting stunningly high memory clocks, higher than 1400MHz, whilst normally the card would struggle to break past ~1220 on LN2. So, it appeared that the memory clocked worse the closer the pot was to the PCB. With the IHS off, not even 1200 was doable, with the IHS, a bit past 1200, and with a shim on top of the IHS, over 1400. It might not necessarily be the memory causing problems in the case of the 580 Lightning, but my guess would be that it's something on the PCB that's getting just a little too cold because the pot is closer to it when IHS-less. (yes, that 2mm is significant)