Why is my custom content crashing my sims 2?

Yo!
i've just installed sims 2 OFB and heaps of custom contents and my game keeps crashing.
I know it's because I have too many custom content but when I had simd and all the expansion packs a while ago and WAY more custom content as well I didn't have this problem. I've installed all the files correctly and there is NOTHING wrong with them so what's going on? and can I get it to stop crashing while keeping all my custom content???