I have very low fps when 3 or more players fight and when a SNAC or a Heavy Mortar explode my game stuck for 3-4 sec and them I see a blue message *DEAD*; this happen and when a Cruiser/Battleship come on my scanner; when I meet a nomad the game fall at 5-6 fps and when meet a galic ship 5-7fps too... and in 1vs1 fights are some fps drops..
My PC :
AMD Sempron 2400+ 1.67Ghz
1.5GB RAM DD1
Saphire ATI Radeon HD3450 512MB
I am not an expert about this topic but the RAM seems to be fine, also the video card. I am just not sure about your processor. Seems like it is working with one core so that could be the reason. But maybe there are other reasons like programs that are running while you are playing that slow your computer down. If it's correct that it is because of the processor with the single core then the only thing you could do is to buy one with two or more cores. But as I said I am not the best about this here.
The game don't need a dual core processor. Here are the system requirements http://support.microsoft.com/kb/814552, from what write there I must to run it with no problems, but I have low fps..This happens in SP(vers 1.0) too.
What Korny said, i suggest you to clean out the PC out of any dust.
And Discovery mod requires more resources than vanilla freelancer but your specs should be ok for fights like that and don't forget that more lasers = less fps
Internet connection is good, max pig was 70 and never had more then 10% loss.
I keep running yahoo messenger and some time winamp.
Some time yes.
I will try.