I have a late 2009 iMac. Here are some specs:
Processor Name: Intel Core 2 Duo
Processor Speed: 2.93 GHz
Memory: 4 GB
Chipset Model: NVIDIA GeForce GT 120
VRAM (Total): 256 MB
Problem: I'm suffering from very poor performance/low FPS. My settings are set to low and I usually play in 1240x786.
The thing is that I can play mostly fine in Act1&2 where framerate is very good. Act3 is the problem. Also, it gets better the 'longer' I play i.e. the framerate is very poor for the first 2-5 mins or so but then it gets fine (but sometimes i does not).
I tried lowering the resolution a bit but it didn't really change anything.
Is there some optimization I could do or should I come to terms that this Mac is outdated?