One single Appliance supports 1M concurrent connections, so a Security Group of 2 Appliances will support 2M concurrent connections.

How to troubleshoot Gaia Portal (WebUI)

https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails= &solutionid=sk91380

VSX R81 Administration Guide

https://downloads.checkpoint.com/dc/download.htm?ID=103853

List of All Resolved Issues and New Features

https://sc1.checkpoint.com/documents/Jumbo_HFA/R81.10/R81.10/R81.10-List-of-all-Resolved-Issues.htm