I have a simple project, using lots of layers, but no effects. It takes more than a minute for the project to open, after which the interface becomes slow and unresponsive and doing anything in general is a pain.
I've tried changing settings relating to multi-processing. Currently I have 1.5 GB assigned to each core and it tells me it can use 7 cores as a result. I've assigned 13 out of the 16GB or RAM I have for after effects. Caching is also enabled.
The only thing I can think of is I can't enable the GPU for rendering as I have a NVIDIA GeForce GT 650M with 512M of VRAM. Is this the problem, or is there something else I can try/do differently?
MP is not going to help. Reset your preferences to the defaults. Make sure AE is up to date. There have been several bug fixes. Give that a try. If it's still slow please tell us what you are using as footage and give us some details about the size of your comp. Some footage is harder to interpret than other. One last question, what is lot's of layers? 15, 150, 1500?