For what it's worth, I'm also using an i3 processor and FSX. To improve frame-rates significantly I reduced cars, airport vehicles to zero. Some of them will still show up, like re-fueling and tugs etc. Then I reduced shipping down to five per cent using the slider. On top of that I tweaked the entire FSX scenery configuration file found in the AppData folder under Roaming. I'm enclosing a copy of my configuration for you to use. Just make up a copy of your original one in case you want to revert back.
Basically I added a Memory fix onto it to reduce resources that your computer draws on, in other words, a Memory Maximum. It cuts out tearing and should give you 27FPM which is very reasonable. I have another tweak should you require it. Anyway, just replace the file I'm giving you for your original.
fsx.zip