I found out that my Surface lagged alot and Antimalware Service (or something like that) was eating a lot of resources. I went and opened Windows Defender configuration, but there was no disable option like on desktop. Then I started looking from registry and found a way to disable Windows Defender. Here's how:
If you have jailbroken your device, you can download the attached app that does everything for you. Source code can be found here.
If you have win86emu running, you have to right click and select Run as administrator or otherwise win86emu thinks it's a x86 program.
For manual registry editing:
2. Take ownership of the key and add write permissions to yourself (Right click Windows Defender key, click Permissions, click Additional settings, click Owner, type your username and accept. Now on the Permissions window click Add, type your username and check Full Access and click OK)
3. Change the value of DisableAntispyware to 1
Now apps start instantly and no lag is noticeable. I may be imagining but before I did this all apps took forever to start. Please try and share your results. Would someone make a comparsion of app open times before&after?