Actually, you've been plenty helpful, MrsFlynn. Thank you! The thing with the switchable graphics and making sure sims was assigned to the good one has gone a long way, I think. Don't give up on my graphics card yet! This laptop ran my immortal dynasty to completion, even max speed with no lag, so it definitely has the capability to run Sims 3. The Intel graphics, it's true aren't powerful enough; I think that's the integrated graphics in the CPU. The AMD Radeon HD 6490M, however, should be handling this like a pro.
One thing I'm noticing, is that even though Sims is reassigned to the high performance graphics (so it should be using the AMD one), is that while it's loading the screen dims. It's bright, then it dims, and that means crash. It's like it's still trying to use the Intel graphics? I'm not sure. One time it loaded up all bright and ran fine until I tried tabbing out then back in. Then dimming and crash. I've check power options and made sure they're selected to high performance, not energy saving, but that doesn't seem to fix it.
At this point, I may be looking at a full on re-install of the entire operating system. Ah well, if anyone thinks of any more tips, keep it coming!
Thanks,
Rhoxi