Default [Q] Question regarding GSm / Global call setup and battery

So as im researching the problem with my unlocked verizon phone , i bought the phone on ebay and currently using it in israel.
I currently have the phone on preferred network settings as : Global . My question is , if i switch it to the GSM/ UTMS option , will it save battery power ?
or leave it on global network ?
thing is , when i switch it to GSM / UTMS option , sometimes I lose internet connection when not surfing the web on Wi Fi...