Q: MACbook Pro Retina 2013 - RAM Usage

Mavericks is designed to use as much available ram as possible.

If your memory pressure is green, then all is well. OS X Mavericks: About Activity Monitor

Is there a problem with performance, what does it mean when you say it starts croaking?

I wouldn't use memory clean or optimization applications.

OS X Mavericks: About Activity Monitor

Determine which processes are burdening your Mac's resources. Post a screenshot of Activity Monitor with the Memory tab selected, and sorted by the Memory column in descending order.

Make the window as large as possible so that you can post as much of it as you can.

Don't include any personal information in the screenshot.

Memory "cleaning" apps serve no beneficial purpose.

To take a screenshot hold ⌘ Shift 4 to create a selection crosshair. Click and hold while you drag the crosshair over the area you wish to capture and then release the mouse button. You will hear a "camera shutter" sound. This will deposit a screenshot on your Desktop.

If you can't find it on your Desktop look in your Documents or Downloads folder.

When you post your response, click the "camera" icon above the text field:

This will display a dialog box which enables you to choose the screenshot file (remember it's on your Desktop) and click the Insert Image button.

The percentage memory left unused is itself not important. Mavericks will normally exploit system resources to the maximum extent, and it is normal for nearly all of it to be "used".

Performance will become limited when the unitless "memory pressure" graph begins to indicate a status of anything other than "green". At the time you posted that screenshot, performance was not being limited by available memory, and if you were experiencing poor performance at that time something else is causing it.

Please determine if the problems also occur in "Safe Mode":

• Safe Mode or "Safe Boot" is a troubleshooting mode that bypasses all third party system extensions and loads only required system components. Read about it: Starting up in Safe Mode
• You must disable FileVault before you can start your Mac in Safe Mode.
• Starting your Mac in Safe Mode will take longer than usual, graphics will not render smoothly, audio is disabled on some Macs, and some programs (iTunes for example) may not work at all.
• Merely starting your Mac in Safe Mode is not intended to resolve the problem, it's to observe its performance without certain additional components.
• To end Safe Mode restart your Mac normally. Shutdown will take longer as well.