Is there a way to get rid of the lag?

Well,I just love space battles and when i saw SOASE,it was the best thing ever for me.

But yeah,i dotn consider myself lucky,all my RTS games just happen to lag with no fixes.

SOASE,C&C generals(AI using cpu stupidly,single core),Supcom(interface lagg,wonder if Soase hase this problem too) and so on..

in this case,SOASE laggs to me cuz it uses only one core at 50%.That is not fine,cuz with only 1.8ghz processing capacity for one core,thats damn slow.

After 2 hours my fps drops at 5 .I could be finishing games for 3 hours if it was not for the lag,instead one normal games takes 6 hours for me.Normal meaning 4 AI FFA at Cruel.

And yes,its not the memory cuz at th time of total lag,it uses 1.6 gb with six ai's.

So,is there a workaround for this?Or how can i finish one game without lags?

Do small fleet sizes help? Does playing with a weak AI help?Or yet better,is there a fix for this?

This game is awesome but why did not this issue get fixed for so long time?

PS I have searched for answers on this forum but to no result.that is why i am asking this again.

Thank you.

btw,I have dual core intel r core tm 2cpu 6300 1.86 ghz

nvidia 8600 GTS 256 mb

2gb DDR2 dual channel ram