Vulkan's Dota2 gives low fps compared to OpenGL on Steam Deck

[Saroumane]

Your system information

Steam Deck with :

• Stable Steam OS version (as of 11th July, 2022)
• Stable Steam Client (as of 11th July, 2022)

Problem description and steps to reproduce

I noticed a performance problem for Dota2 on Steam Deck. (Vulkan is expected to perfom better than OpenGL in most scenarios)

Steam Deck frame rate limiter is set to : off Dota2 fps limits are set to 240 fps. Vsync is off. No external screen. In "demo hero" mode, screen is centered on river, hero is uphill near the river

1st batch : all Dota2 gfx settings on lowest.

SD in Desktop mode :

• Opengl => demo hero mode : 150 fps
• Vulkan => demo hero mode : 115 fps

SD in Gaming mode

• Opengl => demo hero mode : 150 fps. Dashboard : 160 fps
• Vulkan => demo hero mode : 125 fps. Dashboard : 95 fps

SD in Gaming mode + Steam Offline mode :

• Opengl => demo hero mode :140 fps. Dashboard : 210 fps
• Vulkan => demo hero mode : 115 fps. Dashboard : 180 fps

Now all Dota2 gfx settings are set to the max. Vsync is still off.

Gaming mode

• Vulkan => demo hero mode : 85 fps. Dasboard : 67 fps.
• Opengl => demo hero mode : 104 fps. Dasboard : 93 fps.

Vulkan always performs 20% ~ 30% worse than OpenGL. Out of demo mode (in team fights of real games), fps can drop as low as 20 fps. So every boost is needed :)

[Haxeil]

can't they just bring back Opengl ? not everyone is capable of affording a new gaming laptop, many players suffered from this move to Vulkan.