That's kind of a tricky question. Option 2 is poorly configured (it should have a multiple of 3 DIMMs), but for what you're likely to be doing, Option 1 would be faster anyway (and would almost definitely be if you bumped up the RAM to 8 GB. Either one could run Windows 7 64 bit. And 64 bit is the way to go. In this day and age, the 64 bit drivers are very common, and Windows is very good at running 32 bit software on 64 bit OS.
The only way the 920 would be faster than the 860 is if you were doing a very memory intensive thing (and it had the proper number of DIMMS) using all of the cores and hyperthreading on the processor--not likely. Now, of course, ClubNeon does this sort of thing all the time, so maybe he can speak to the difference better than I.
