How well will this work?

hello, my cousin's birthday is coming up and I'm recycling my old parts for a new gaming rig for him. I'm using my old 680i LT with 2 8800 GTS 512s and my current E6750 when my E8600 comes. I have had many problems getting the E6750 to a stable 3.6 Ghz on this board. One of the bottlenecks I believed I was having was that I could not overclock my memory to match 900 mhz to sync with an 1800 FSB, which would have squeezed out a little more stability. I will be trying to get 900mhz again, but I am not paying another $120 for another OCZ ReaperX kit just to overclock it easily. This leaves me with another idea, I have found some 1000 Mhz RAM for a much better price and I have a feeling that an underclock will be much easier than an overclock. The 680i LT only supports 800Mhz RAM and should default to that, but I know that bumping the RAM to 900Mhz should be simple. What do you guys think? Also do you think my NB was overheating with the stress of the overclocking? I know the damn cooler is about as pathetic as possible, but do you think that would be a problem? I assume the system temp. will be the NB temp, right? Do you think that replacing the thermal paste on it would help? Anyway I just want this thing to perform great for him, and I want it stable. With a 680i LT the stability part is going to prove challenging.