Hello
I've build a system based in a motherboard Asus Sabertooth Z77 (same chipset than that you mentione) and I see a big improvement in FSX due to Lucid MVP.
My system is:
Asus Sabertooth Z77
Intel i7-2600K at 4.8 GHz
8 GB of RAM (1600 MHz - CL9)
After the FSX installation, and with the default FSX.CFG, all the visual settings (scenery) maxed and no addons, I fly over New York with more than 20 fps. Without Lucid MVP the frames dropped to 10 or even less in the same scenery setting.
In my opinion you should try to install Lucid MVP. Isn´t necessary any changes in FSX after that. It's "plug and play" and if you don't like you could uninstall it.
Best regards
Joaquim Xavier