If there are no specific needs, choose x86_64
system images with Google APIs to create the emulator.
It works way faster than armeabi-v7a
on intel x86 x64 based computers.
There are some SDK libraries compiled and designed with ARM architecture.
If you try to install them on Intel based emulators you'll get an error message saying
"INSTALL_FAILED_NO_MATCHING_ABIS"
You can go for a 3rd party emulator like Genymotion or Visual Studio's standalone Android Emulator on such occasions.