I'm absolutely no expert, but if it's really about noise, isn't good noise-cancelling headphones a much cheaper investment than more walls?
I'll tell you what, though. Working at a table on a laptop all day is really bad for neck and eyes. I miss my big, eye-level monitor.
Using cheap tables, giving your employees laptops without external keyboards and stands and using big, bright florescent tube lighting is terrible for workers. It harms their bodies and hurts productivity.