To modify the registry settings you need to install the right version of Interop Tools (1.9.390.0) for TH2 builds, don´t install the version from store, it will not work on your build. Be very careful, if you modify the wrong values in the registry your device might become unusable ("bricked")! When I did this I had my Lumia 925 as my backup phone.
1. On your PC, Download the right version of Interop Tools from
https://forum.xda-developers.com/showpost.php?p=70175971&postcount=513. You just need Dependencies_ARM.zip and
InteropTools_RC-1.9-pre10_arm_1.9.390.0.zip the other ones are for pc and will not work on the phone. Put all the APPXs (including dependencies) on your phone storage (e.g. Download folder)
2. On your phone. go to Settings > Update & security > For developers
3. Turn on Developer mode, Device Discovery and Device Portal
4. Open Microsoft Edge on the phone, and go to
http://127.0.0.1/ to open Device Portal (it is possible to do this using your PC via WiFi but it'll be slower since the APPXs need to be transfered via WiFi)
5. If there is a certificate error, ignore it and click Continue to this webpage
6. You might be asked to authenticate. Go to the previous developer settings and click Pair button
7. On the Device Portal, Click Apps on the left sidebar
8. Install all Interop Tools dependencies ONE BY ONE. After that, install the main Interop Tools APPX
9. Turn off Device Discovery and Device Portal on the developer settings
10. Open Interop Tools > This Device. Open sidebar, choose Interop Unlock
12. Check Restore NDTKSvc and restart your device (on some occasions, the other option can't be turned on until you restart your device)
13. Open Interop Tools again - click on This device - Open registry browser and navigate to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PagingFiles
14. Change the values 256 256 to 1024 1024 (remember the spacing in between the numbers) and save
15 . Restart your phone
Check Settings - System - Storage - This Device - System&Reserved. If the change was successful virtual memory should now read 1,00 GB instead of 256 MB.
I have the lumia 925 with 1GB RAM and 16 gb internal storage. Multitasking will be faster when you want to switch from one open app to another and you can have more apps open at the same time after increasing the virtual memory. From what I've read some memory intensive apps might work better.
Interop Tools can also be used to modify your phone model name to enable you to download Anniversary Update should you wish to do so later.