macbook so slow for about 10-15 minutes then better

The very first thing that hits me is you need more memory. 2GB is not enough for El Capitan. When waking from sleep, you are reloading whatever launch agents you have installed. And if you have put hard drive to sleep in the system preferences energy, that will also slow things down at first.

In sounds like a possible impending hard drive failure to me. I would suggest downloading the free trial version of this software to verify the health of your hard drive. If it finds problems, you should backup your hard drive as soon as possible.

https://www.volitans-software.com/apps/smart-utility/

Most of what is in launch agents are part of system software. The only thing you could check is anything you have added to your computer that has startup or launch agents. Some of which can be check in system preferences users. In removing any software you should use an uninstaller if it came with the software or go to the website for that software to see how to uninstall.

Is it Time Machine doing a backup? I noticed Time Machine was making my MacBook slow once, it was doing something to the local disk when it was time to do a backup and my external drive wasn't connected. I put Time Machine Off in the Time Machine Preferences and now force a back up with Back Up Now after I attach the external disk.

Launch Activity Monitor to find out what's running and look for processes hogging CPU or memory.

Activity Monitor is an application located in your Utilities folder.

Sort the column for CPU usage to identify the apps that may be using excessive cpu cycles.

DJP from Mich wrote:

Thanks - there's a Lot of stuff in that activity monitor (much of which I cannot tell what it is) (and btw I keep trying to mark your responses as helpful but its not working on your posts)

You can only mark two responses per question as helpful. So, you're not doing anything wrong, that's just how the forums are set up. 🙂

In the activity monitor the most memory or cpu usage will be in order of use from top to bottom. Kernel task is made up of what you see in the rest of the columns under root. The others are your user name. For running El Capitan 2GB of memory is not enough. 4 is minimum and the max you can install is 8.

You are correct. it will handle 8GB http://eshop.macsales.com/MyOWC/Upgrades.cfm?sort=pop&model=300&type=Memory Here is a video on how to install the memory yourself. http://eshop.macsales.com/installvideos/macbook_13_unibody_mem/ As you can see it is not that hard. Also mac sales has a good price and their memory is guarantied.