On the left is the leaked Roku 4 photo found on Roku.com, and on the Right is an Nvidia Shield with the 2014 Roku 3 remote. While we can’t get the angle or the distance to the streaming box 100% right, it is safe to say the Roku 4 looks to be much bigger than the Nvidia Shield.
The Shield is already one of the larger streaming boxes on the market today, but the Roku 4 looks to be wider and taller than the Shield. Now the shield does pack a lot of stuff in that space, including a 500GB hard drive.
The real question now is what does Roku need with all that space?