My macbook pro is using all its RAM

Mavericks manages RAM differently than previous OS X, it uses all available RAM- this is normal.

You can read more:

http://arstechnica.com/apple/2013/10/os-x-10-9/17/#compressed-memory

In Mavericks, regardless of how much RAM is in use, there is not a critical RAM problem unless you see two signs: Compressed RAM is very high, and Page Outs are very high. Still, if the Mac seems too slow, it probably means that whatever application you are using really needs more RAM than you have. (4GB RAM is pretty minimal these days, I won't use a Mac with less than 8GB for my work).

If you can upgrade the RAM by adding more, that would be the best solution. If you have a non-upgradeable Mac, there isn't much you can do. Reformatting probably won't help, because if your applications really need that RAM they're going to take it again on your reformatted system.

One thing I have noticed with several users: They run their web browser open with a million tabs open. It is shocking how much RAM this can take up. This one thing would be enough for them to run out of RAM on their 4GB Macs. Two different users I know could not shake this habit, so I just told them to buy and install a couple more GB of RAM and now they don't have any more RAM slowdowns. The reason I bring this up is because maybe you unknowingly keep many applications open, or even just one application with many documents and tabs open. If so, if you can minimize the number of applications and documents you have open on a Mac with only 4GB, that might help. But if you are already running out of RAM with not much open, I'm not sure what you can do. I am pretty sure that reformatting isn't going to make much difference.

Have you installed any anti-virus software or those "I'll clean your mac" programs?

Yes.

In General 3rd Party AV Software and Cleaning Utilities tend to cause More Issues than they claim to fix...

They are Not Required..

jssaren wrote:

I think Ill just increase the RAM to 8Gb and see how it runs. Not sure if my mac can handle two 8Gb cards to make it 16.

You can use these Links to check which RAM is suitable for your Mac...

http://eshop.macsales.com/shop/apple/memory/

http://www.crucial.com

Macs can be very Fussy about RAM...

It is Important to get the Correct and Matching RAM

Those sites also have videos on how to Install RAM should you need it...

Buying RAM may be a waste of money. As has already been said, Mavericks will do what it can to fill RAM entirely, on the philosophy that free RAM is wasted RAM. This allows it to keep your system running faster. Blaming your issue on full RAM is like looking at someone with a cold, noticing they have ears, and deciding that those ears are the source of the problem.

If RAM is the problem, the memory pressure graph in Activity Monitor's Memory tab will get high, and will change from green to yellow or red. Keep an eye on that graph. If it's not yellow or red when you're having performance problems, those problems are not due to RAM.

Even then, though, the problem could be caused by junk software you've got installed if that junk software is eating up RAM like candy. MacKeeper, Kaspersky and CCleaner are all what I would categorize as junk software, highly likely of causing performance and stability problems without any chance of solving any problems. If you've had those installed, chances are fairly good that you have other junk software installed as well. This is the core problem, and needs to be solved before spending money on RAM.