VideoCommon: Increase uniform stream buffer size to 64mb

[TellowKrinkle]

Densha de GO! Shinkansen EX uses 27mb per frame, and we want enough space for the CPU to be encoding one frame while the GPU is rendering the previous

Increases frame rate for Vulkan and DX12

In the scene mentioned on https://bugs.dolphin-emu.org/issues/12920
Vulkan (i7-4980HQ, GT 750M) 22fps → 35fps
Similar improvements on an AMD Radeon Pro 5600M but I'm too lazy to boot into Windows for an exact measurement right now

[JMC47]

Is the game still not full speed? I don't know if it's a 30 FPS game or 60 FPS game.

[TellowKrinkle]

60fps game. Not full speed.

[JMC47]

Yikes, that's a monster of a game I guess.

[TellowKrinkle]

Definitely pretty evil
The closest I've gotten is...

• Enable Dual Core (normally disabled in the INI for breaking some other rendering)
• Metal renderer
• Exclusive ubershaders (Game swaps between depth write on/off. With normal shaders, that swaps between an early-z shader and a non-early-z shader, but on ubershaders that keeps the same early-z shader the whole time. In Metal, z write settings are not part of the pipeline, and swapping depth settings is easier on the CPU than swapping pipelines. DX11 might also do well here, but the only computer I have with a fast enough GPU to run exclusive ubershaders is the AMD one, and its DX11 performance in this game is terrible compared to Vulkan.)

And it's still in the high 50s

It's entirely CPU limited, so a cpu with good single threaded performance will probably help. My fastest computer is a Coffee Lake laptop, so a Zen 3, Alder Lake, or M1 might do a good bit better.

[JMC47]

Sounds like we need to somehow optimize whatever is bottlenecking the game to make it realistically playable.