My rig isnt really "high end" depends what you mean by it, but its a pretty decent one. my specs are
Intel i5 2400
Gigabyte gtx 560 ti OC'ed
4GB or ram
Im starting to lag a bit my city grows bigger which is normal from what i have read, but to my understanding this is a pretty old game and i should not have any lag at all with my specs so...IS THIS JUST NORMAL? thanks.
I used to play it without lag in a 6600 non gt waaaay back but when i upgraded to a 4650 some years ago (and a dual core cpu), even medium sized cities lagged so bad unless i switched from hardware to software render mode in graphics options, and it still was slower than a pentium 4 with a geforce 6600.
Using the same 1024x768 resolution of course, because i had that 15 crt for almost a decade..
Software render disables GPU acceleration so all the work is done by the CPU.
Normally that would make any modern game unplayable but SC4 is old and has mostly 2D graphics on 3D terrain (still not recommended).
I don't know how sluggish your game may be however, as i recall the problem i had was exclusively from of ati cards, and in a city with 800k+ pop i was getting 0.5 - 5 fps (hardware mode) and ~15 fps software mode.