Here is a link to a youtube channel of games being played on the Microsoft Surface Pro 1, 2, and 3. The Surface Pro 1 and 2 uses Intel Core i5-4200u / i5-4210u CPU with the Intel HD 4400. The Surface Pro 3 uses the newer Core M 5Y70 with the Intel HD 5300. The Core M 5Y70 CPU is a bit slower than the i5-4200u / i5-4210u, but it uses less power and does not need a fan to keep it cool. The Intel HD 5300 is more powerful than the Intel HD 4400 though.
https://www.youtube.com/user/microsoftsurfaceproG
Actually, the person seems to be using different models of the Surface Pro 3 so some of the videos with the Surface Pro 3 may use a CPU that is not the Core M 5Y70.
Note, you are seeing the actual performance of the Intel HD 4200, Intel HD 4400 or Intel HD 5300 (depending on the model) because he is using hardware to record the video. He is not using software (like FRAPS) to record gameplay.