I got this from the Howto on the SC4 Rush Hour entry and it sped up mine considerably:
Open regedit with the command "wine regedit" (no quotes) to change the values.
[HKEY_CURRENT_USER\Software\Wine\Direct3D]
"VideoMemorySize"="NNN"
Replace NNN with the amount of VRAM your card has.
By default wine guess you have only 64.
[HKEY_CURRENT_USER\Software\Wine\Direct3D]
"DirectDrawRenderer"=""
gdi - Use GDI to draw on the screen (slow but reliable) (default)
opengl - Use OpenGL (fast but not all programs work correctly)]
Since most user do not have a clue about debugging wine, you can set the following variable:
WINEDEBUG=-all
wine will have no verbosity and will not display any debugging information.
Also, adding -d:opengl to the end of the launcher can increase performace, but TBH I don't notice that much of a difference between that and software rendering. I personally use -d:software, which to me works best and is most playable, but you can try opengl if you want.
Here's the command that I use to start simcity 4:
WINEDEBUG=-all wine C:\\Program\ Files\\Maxis\\SimCity\ 4\ Deluxe\\Apps\\SimCity\ 4.exe -d:software -intro:off
If your game is crashing randomly...
If your game is randomly crashing every ~20 minutes or so, try adding this to your launcher:
-CPUCount:1
It seems to be an issue with dual core CPUs that previously didn't cause problems (by the way it has problems with dual core CPUs in Windows too sometimes), and I tried taskset and it didn't seem to help, but so far adding -CPUCount:1 seems to have fixed it.