Power-Inside

I have two computers on a local LAN connection and we both use it to play MTA SA (1.0.4) One PC has a lower grade single core CPU so it gets an average of 15 to 17 fps and only at times 29 fps etc.. The new PC gets a constant fps of 30. So when we play RACE modes, the player of the 1st PC always seem to degrade in speed and there is virtually no way for that PC to win in a race in MTA. The latency etc is excellent ( 1- 2 ms ping and no more than that i guess) What to do to lower FPS on the 1st PC? I've turned down all the details.. but the particles and motion blur seems to be one root cause of slowdown. So is there anyway/ any software to disable these or increase gamespeed? Also , why is MTA showing considerable failiure in this regard? its only a small difference of FPS and still? Will MTU tweaking help?