Q: MacBook Pro is slow

How much memory (RAM) do you have?

Open up System Information or System Profiler and select "Memory" in the bar on the left side.  What does it say for your status?  It should say "OK".

Do you use Safari and have lots of tabs / pages open often?

Open the Activity Monitor. From here, click the 'System Memory' tab at the bottom. Check the Page Outs and post it in your reply. Note this number resets everytime your machine reboots.

Look for possible reasons/solutions here:

https://discussions.apple.com/docs/DOC-3521

Ciao.

You need more RAM. Page outs mean your physical memory has ran out, and your CPU must use your hard drive as a scratch disk (the purpose of 'the swap space'). This will slow down performance greatly. I recommend purchasing upgrades from either OWC or crucial. Reputable companies who offer warranties on their RAM modules.

Apple Mac Memory Upgrade Options:

Purchase compatible RAM for your machine from the sites suggested and see this article:

MacBook: How to remove or install memory - Support - Apple

"Pages Out: 3.46GB (0 bytes per second)"

Withstanding the very unlikely event of a massive memory leak by a piece of software you are running, yes, you need more.