Speed up blender

What is the best upgrade I could buy for my computer to increase the detail I can have on a mash before blender starts to slow down?
I have this problem.
I have a good graphics card, but not optimal.

Okay, I’ve followed all the instructions. certainly helps.
So now I should buy more RAM?

It’s hard to give any advice on what you might need to improve when you don’t say what your current setup is.

More RAM does mean you can have bigger models open without Blender crashing, but the CPU still has to crunch through the data. i.e. you’re not necessarily going to get any more performance out of it by sticking more RAM in. Also, remember if you’re rendering in Cycles on the GPU, system RAM means nothing - it’s all about how much RAM your graphics card has.