@ Drunkenvalley; It depends. Since they will use twice as big memory modules rather than twice as many (else it'd be a 512 bit membus, or two would have to share channels), it all depends on the PCB, as always. Same pcb, just more memory? Get the same waterblock.
Wait what speakers/phones are you using it with again?
Also, tried playing with the equalizer?
Some people don't even bother playing around with their equalizers to find out how their speakers/phones react to it and if they can improve their listening experience *cough* Deltrus *cough*.
I'm not even using 'good' stuff. I got an old Altec Lansing speaker system with noise issues (poor design in the sub - amp and power supply are practically right next to each other). Also using a pair of Sennheiser PC330's. They're good, but not super enthusiast headphones by any stretch. Even then, the difference is night and day compared to the old X-Fi. I know what's going on my giftmas list... 'spensive Sennheisers!
Well atleast you have the option of putting it below your GPU >_> I have mine pretty much frying against the GPU backplate because it can't go anywhere else...I've wedged a piece of cardboard between the two so the heat doesn't conduct straight from the metal backplate to the metal STX shielding.
But I read that the circuitry/caps on the STX can withstand up to 125c, which is neat