First of all, I'm really sorry to post this here! I know this should belong to the Syndicate forum, but the urge to play this smoothly is too tempting :P

So anyway, when I move my mouse fast in-game, SW starts to lag like no freaking tomorrow and go batshit crazy ?
Also, there are HUGE fps drops while explosions are on screen.
I've tried the Windows port but didn't like it since the mouse is all laggy and pretty much unresponsive unlike here, where it's silky smooth and the overall performance is superior (minus those couple of annoying things which break the game :c )

Sorry for the long post and my crappy english. I'm taking all advices in (giggity) since this is probably my third favourite game of all time! >__<

Does your system meets the minimun requirements for the game? I know that this is probably not the problem, because the game is not hard to run, but just to be sure.

I can't remember if this is a DOS game or not.

If it's a DOS game and you have a newer graphics card, you should try switching to openGL.

If it's not a DOS game, more info about your system would help others give advice.

Mainly:

CPU:
Graphics Card:
OS:

Sometimes the older Windows game will improve performance by running in compatibility mode, and sometimes running in OpenGL rather than DirectX will improve performance (really depends on the card, sometimes running in OpenGL will worsen performance, I've personally seen both).

Also to ask is how much Physical memory do you have Vs Virtual Memory.

I've seen computers with 100Mb or so of ram trying to run 300Mb of background services....

I'm pretty sure it's the DOS version running in DOSBox, so there are probably some adjustments in the config file that could be done.

See here:
http://www.gog.com/forum/syndicate_series/syndicate_wars_performance/post4
;-)