It's actually far from being optimized. As I mentioned,the texture remains only for a while. The longer you play the game the more texture disappears. And don't forget the taxi bug(fixed partially with the consequences of crashing even more often). Also,here's my VERY-simple commandline if anyone is interested:
-norestrictions
-nomemrestrict
-disableimposter
-reservedApp 0
-noprecache
-novblank