I asked another question about memory use, as it seems that Task Manager was not reporting memory use correctly -- the total used sum was far more than the sum of the individual programs' use. I learned about a new concept of "Mapped Files" (as per RAMMap's memory report).
Anyway, while Task Manager reported that I was nearly filled to capacity memory-wise (which must have been largely to Mapped File use, as the programs' sum didn't come close to the actual total 12GB of available memory), I went ahead and ran Max Payne 3 anyway, to see how it'd fare.
It opened and ran fine, with no sluggishness, but Windows popped me back to the desktop and informed me that it detected that my system's performance was sluggish, and suggested dropping my color scheme.
What is Windows basing this analysis off of? I'd assume it has to be (largely) memory use, as my system's CPU use at the time was probably a total of 20% or under.
If it is memory-use, it's frustrating because I feel like it's almost impossible to know when you're actually pressed up against your system's memory limit, vs. Windows only temporarily caching/mapping files (sort of like a "phantom" measure of use, deferring to future programs needs).
It also worries me because when the memory limit fills up, even with merely Mapped Files, it sends my page file rocketing to 6GB, leaving me to fear that Windows is now "grinding" away at my SSD as a full-fledged, temporary memory-stick.
MY SYSTEM Windows 7 Ultimate 64bit Core i7 930 @ 4.2GHz 12GB 1600MHz ram 160GB SSD (main OS drive) 1GB page file, expandable to 6GB