Like was said earlier in this thread unless your multipliers alot higher you probably wont need ln2 at all for the processor. At 5400+ depending on the voltages you might need a DICE + acetone mixture. Instead of little warmer DICE + Isoprophyl mixture. Otherwise a SS Phase Change system will pretty much have you set.
Bobnova and I where running DICE on my 2600k + Maximus IV extreme lastnight. Instead of my normal SS system. Until we switched to the DICE + Acetone setup the temperatures did not drop below that of my SS setup. (which is around -10c to -6c at the core approximately, external sensed temperature of -44c to -48c). Acetone mixture did help maintain the temperatures alot more consistantly than my SS.
We where running at 5.5ghz at 1.47v vcore, 1.2v cpu_io, 1.05v cpu_sa. Voltage wise thats really not that high. We didn't do any 5600+ runs, due to time.
If you can get a SS phase change system, thats capable of around 300watts of heat transfer you will proably be fine (and better off than i am, since mines only capable of 120-170watts maxx).
Not exactly what you asked for but figured it might give you an idea of what your looking at for the i7 setup.
As for quick boints on ln2. Like hokiealumnus said, Phenom II's scale like crazy with cold. My 140watt 940 deneb got a 500mhz jump out of going from air to the SS, and its still asking for more cold. Just going that cold with one should yeild a good amount of points. I got around 15-20ish just doing superPi runs at 4525mhz.
