Who doesn't?
For the average user, 4 MB is plenty in 2010. You gain speed by having more of a program running in RAM. In fact, RAM is usually the most cost-effective way to speed up a computer. If your programs/project size exceeds your RAM space, you spend more time accessing the HD. Also, having many programs open at once is possible.
That having been said, I'll repeat: for the average user, 4 MB is plenty in 2010.
I think you mean GB![]()
The more, the better. But $300 (to upgrade to 8GB) is a lot of money.
I have 4GB RAM on my current laptop and it runs Photoshop just fine (with moderate use - not too heavy). But when I run Photoshop with several apps (mostly iPhone, Safari, iTunes, and some times VLC?), it lags a lot. But that's because my Macbook is really old. I don't think you will have any problem with 4GB on current models.
Virtual machines like Windows XP on VMWare can used a decent amount of RAM. When I'm multitasking and using VMWare, I like to have more than 4 GB of RAM. This is where 8 GB would be useful.
Other than things like Photoshop, is 8GB really necessary when it comes with 4GB?