DeskRoll Remote Desktop relies on the WebRTC technology to establish direct, peer-to-peer connections between you and your customer/unattended computer. Currently, Chrome and Firefox are the WebRTC-enabled browsers that can make p2p connections in DeskRoll.
This means you most surely will get faster connections with Chrome or Firefox. Just start one of those two, login to DeskRoll and work as normal.
When you are in a remote session, you might want to look at the viewport title bar.
Right after the remote host name, there should be a (P2P) suffix.
If there is no such suffix, then DeskRoll could not make a p2p connection, so it is using an intermediary server to send all the data.