Did you pay this 1.1k recently? A 5200 sounds low for a brand-new top-spec machine.
It sounds like your connection is the problem, but MTA always has a bit of lag anyway, as you'll notice if you play it on a LAN.
I'm not sure that turning the frame limiter off would achieve much. The frame limiter keeps the game running at a steady 30 fps (if I recall correctly) to stop it playing too quickly on high-spec machines. If you have a low spec machine that lags online because of its spec, turning the frame limiter off won't make a difference because it will still churn out frames at less than 30 fps.
The frame limiter speeds up your game and so you'll move very fast on other people's screens. If your connection isn't very good, you'll tend to jump even further across the screen than before. Some people use enhanced speed to their advantage and so that's why they've forced the frame limiter on with the upcoming MTA Blue.