The best way to do it is by shrinking the OS to give you the max space on your BB, below, is a detailed step by step guide on how to do this.....follow it carefully, and you should be good, after backing up your settings with DM, make sure to close it as it would interfere with the apploader.
Download OS 18.104.22.1684 or any other OS 6 version you wish, I am not sure which is the best one for the 9650 as I don't have a 9650, maybe someone can suggest the best version, the one I mentioned here is the latest one (may not neccessarily be the best though)
1) Launch BlackBerry Desktop Manager and create a backup of your phone just in case something goes wrong.
Backup your apps using BBSAK if you are really worried that the automatic backup of apploader fails so you can reload them back later on using the BBSAK backup, this step is not mandatory unless you are really worried or don’t have the links to restore all the apps back easily later on.
2) Ensure that you do not have any previous OS installed on your PC by going to Control Panel and uninstalling any BlackBerry Device Software that you see there.
3) Navigate to C:\Program Files (x86)\Common Files\Research In Motion\Shared\Loader Files and ensure that folder is empty, if there was any folder in there (usually any previous OS files will be there), then delete it, that folder needs to be empty before we start.
4) Download and install OS 6 for your 9700, you may choose any build you want.
5) Download and install BB Hybrid Tools v2.4
Run Hybrid Tools, click on the Shrink-A-OS Tab then carefully start checking the boxes of the components you will not use, like all the languages, all the carrier themes, the built in wallpapers, videos, etc. ; all the chat/messaging applications that you know you never use, social feeds, podcasts, etc.....
After selecting all the components / languages you want to shrink, click on the Add/Remove button on the bottom right to initialize the shrinking process, when it is over, you will see at the bottom right by how much was your OS shrinked (in MB)
DO NOT REMOVE ANY LANGUAGE FILES UNLESS YOU DONT NEED THEM, ENGLISH UK CAN SAFELY BE REMOVED IF YOU DON'T USE IT AS ENGLISH USA WILL ALWAYS BE THERE BY DEFAULT.
The below image are the options that I select to be removed, feel free to change anything according to your requirements.
6) Navigate to:
Computer >>> C: >>> Program Files >>> Common Files >>> Research in Motion >>> Apploader
Computer >>> C: >>> Program Files (x86) >>> Common Files >>> Research in Motion >>> Apploader if you were using a 64-Bit version of Windows
Then delete the file named vendor.xml (only if it was there, if it wasn’t then don’t bother)
7) Run apploader.exe within that same folder to start the OS update.
8) While getting the options of components to install, you should now see much less as you have shrunk your OS, however, still do a final check to ensure that everything that is checked is something you actually use. Sometimes for example, the Chinese language or any other language or component might be there, so just don’t select it if you don’t want it.
I would personally not bother with social feeds as well as it is of no use to me, saves me some space not to have it. (This is a personal choice, if you need it, then keep it)
What social feeds does is it interlinks all your social apps such as facebook and BBM, twitter, etc, into one application, so for example if you want to set your status as gone on holidays, you don't need to do it on each application seperately, social feeds will do it for all in one step. Still, I personally dont need that.
Next come podcasts, if you don't deselect that during the installation it automatically gets installed, again, useless to me. TuneIn radio is much better IMO.
Last, I do not install Appworld as I can just download the apps manually from the websites, that saves me some good space too. (This is a personal choice, if you need it, and if it works in your country, then keep it)
If you do the above tricks, you should not run into many memory problems.
Follow the white bunny...