I have 8.1 and a 9 year old graphic card. I won't bore you with how to get these graphic cards working on your computer but the most important thing is to have your COMPUTER UPDATED. Windows 8 does a
fantastic job of figuring out your graphic card drivers without assistance but you have to let the update run. The Sims 2 Ultimate is patched for 8 and 8.1 too. I'm not running Sims Ultimate under compatibility mode.
Sims 2 crashed the first 2-3 times I loaded it. The first few times it load it seems to be a mess for pretty much everyone. I changed nothing but it suddenly started working smoothly. Try rebooting in between. I suspect there`s some left over installation issues it goes over during the initial load. if none of that works then:
Try
this link that`s been floating around this page and if that doesn`t work...
Go
here a general help thread on Reddit where you can ask more specific questions if you're having trouble.