gtx 1080ti sli

Hi :) I've got a simple question regarding gpu VRAM in my first ever SLI setup. Here are 2 dxdiag screenshots with: SLI disabled: http://imgur.com/a/djk3w SLI enabled: http://imgur.com/a/wWWya Is this slight decrease in VRAM normal? Also dxdiag isn't the only application that is reporting...