This and similar arguments have been made and had on this forum over and over and over, i.e. I meet the min specs, so why does the game run like it does ?
It was clearly stated in the manual and other posts on this forum that users will be able to run the game but only with details turned way down which will make the game look worse than an early 90's flight sim.
Win7 64bit is recommended (yeah another word for "must have"), but at least you have vista 64bit.
Seroiusly buy a better card, mine is not the latest and greatest either but I have no issues running the game and by now it is possible to pick up one at a very low price, though if I had to buy a new one and could afford it I'd go for nvidia gtx560 and up, maybe with more than 1.2gb of vram.
Plus there are many discussions here about performance, a lot of helpful tips and posts, though I am convinced that upgrading your card will let you enjoy the sim in a much better way.
There are also a lot of tutorial videos available, especially about startup procedures for various planes. I agree, the manual could have been much better, but a little bit of looking and reading around will get you in the pilot's seat successfully.
Good luck
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