Trying to squeeze every last bit of performance out of that machine, eh?
A lot of stuff he changes should auto-detect properly on your system unless you have buggy hardware or software etc. Other stuff he changes is just personal preference and I doubt has any impact on FPS (like saturation). A lot of the ingame video settings you can think of this way: higher detail / higher numbers will result in less FPS. IE, if you had already lowered a setting and were to increase it to match his suggestion you may lower your FPS.
Also, he may be running dev branch as my Arma3 launcher still doesn't let me allocate more than 2047 memory.