Here's my two cents based on my experience in beta 4
I'm running a laptop with an AMD turion ML 40, 2.2 GHZ (single core), 2GB ram and Nvidia 7900GS 512 MB, Win 7
I have the resolution set at the second to highest and have anti aliasing turned off. My machine does not like the antialiasing at all. I look at it this way, I've never been able to see the game with antialiasing turned on so I don't know what I'm missing.
It takes forever to start a new game. Initially building the world takes anywhere from 5-25 minutes, maxes out the cpu, and sometimes crashes. However once the world is built I have no problems running the game. Loading a saved games takes seconds. I've finished a game on both novice and beginner levels although the end seems kind of abrubt. In both cases I got somewhere between 600-700 turns and just suddenly got a popup that I'd won. I forget the exact wording but it seemed to me there were still other kingdoms left to conquer, spells to learn, etc. I'm writing that off to it being the beta version.
I'm by no means a hard core gamer and don't have the money to spend on a new machine right now so I'm making due with what I have. The settings I've listed above worked in beta 4 so I'm guessing they'll do for the release version.
The CPU on my machine is definitely the laggard in regards to the requirements but still seems to get the job done once the world is built. I think the rig you have should do fine. Just an aside,......my cpu is not just the laggard its really flaky,......I posted a different thread here about my issues with CPU performance. I have run the windows experience index a number of times and my cpu is consistently the lowest score on my machine coming in anywhere from 3.0 to 4.2. I tried a number of things (updating drivers, updating bios, uninstalling software, cpu-z to check clockspeed, I even cleaned out the fans and exhausts just for grins) and there doesn't seem to be any rhyme or reason to the score. While I was working on the issue the index started at 3.6 dropped to 3.0 and last night was went back to 4.2 (the original score the day I bought it 3 years ago). I had made changes between the 3.6 and 3.0 scores but did nothing else between 3.0 and last night when I ran the index and got a 4.2. Something in the back of my head tells me the cpu is going to just burn out soon. Anyone know where I can find a Turion ML 40 or 44 ? Havent found anything on Amazon or Ebay (well nothing thats reasonably priced anyway)