I got the new Surface 3 with 4 GB memory this week and even if I did not get it play games I had to test how it performs. So, I installed The Lord of the Rings Online on external hard drive and gave it a short spin. Loading times were long, but the game started. In the open I got between 36 fps in Bree-land and 18 fps in West Rohan with Very Low setting.
So far so good and went on to try some real action. I was able to complete Thievery and Mischief skirmish in solo mode and while the skirmish was playable the low frame rate made it was not that enjoyable with 10 – 20 fps and Type Cover’s trackpad.
Next I plugged in external mouse and keyboard. This was where the problems started. The single USB-port on Surface struggled to deliver enough power for the three devices. The game was still running and I tried to do some questing in Aldburg. Here the game started crashing constantly and I had to quit.
In conclusion, the Surface 3 with 4 GB memory can run LotRO, but with uncomfortably low frame rates and the heavier regions like Rohan can be unstable. I did not research further whether the instability was caused by the game or too many connected devices. The game took almost all of the memory, so the 2 GB model will probably be unable to start the game.
[Edit: 28.12.2015] I made a follow up post.
[THE LORD OF THE RINGS ONLINE™ interactive video game © 2015 Warner Bros. Entertainment Inc.]