Terrible main menu performance with Marci background on Linux

[Xinayder]

Your system information

• System information from steam (Steam -> Help -> System Information) in a gist: https://gist.github.com/Xinayder/94a8db2772849de4bca13853a3f05d27
• Have you checked for system updates?: Yes
• Are you using the latest stable video driver available for your system? Yes
• Have you verified the game files?: Yes

Please describe your issue in as much detail as possible:

Dota 2 main menu background with Marci has terrible performance, I get around 15-20 FPS with the new animated background. Meanwhile, other backgrounds had much better performance, for example, the TI10 background had 80-90 FPS.

Steps for reproducing this issue:

1. Launch Dota 2

EDIT: my system info reports Intel HD Graphics but I run Dota 2 on a dedicated GPU, a Nvidia MX250. And my laptop is an Acer Aspire 5 54G.