Sim City 4 Rendering

I have a problem, I play Sim City 4, and I make big cities. Everyone knows that big cities can destroy the software rendering, which is inferior to hardware rendering, but that's where the problem comes in. I use an ATi 4870, so I should have absolutely no problem running this game no matter what the city size. Problem is, when I switch the game to hardware rendering, the cars and street lights, and even roads, flash in and out, and sometimes don't appear until 5 minutes after I lay them down. It's rather annoying, seeing as the game crashes when my city is approaching 200,000 sims. Anyone know what the issues are?

Oh okay, thanks!