ParaLLEl faster when fast-forwarded? (Not as obvious as it seems....)

Here’s a puzzler. I’ve been trying out the fantastic new ParaLLEl core with proper GFX and RDP settings, and everything I’ve tried runs at full speed with basically no hitches… except Conker’s Bad Fur Day. I know this has always been a problem game to emulate, but what surprises me is this:

The sound sputters and the FPS drops to around 40 during the menu intro unless I hold down the fast-forward key, in which case it jumps to 70 or more with near-flawless sound. Furthermore, if I disable Vsync, it runs at 60 pretty consistently, though with the expected frame timing jitter. (Fast-forwarding without Vsync delivers in excess of 300… but only because the game itself hangs, though it can be rewound to before that and it runs fine unless fast-forwarded again.)

So what’s going on here? Is this a known and expected behavior, or something unique to my setup (a Radeon RX 580 as an external GPU in a first-gen Razer Core)? Any ideas?

Oh, one thing I forgot to mention—

I got the clever idea to cap fast-forwarding to 1.0x speed and then just toggle it on for gameplay as a temporary workaround. Sadly, that only gets things to around 45FPS.

Seems to be a Vulkan issue. This happens to me with Citra and ParaLLEl (only cores I need Vulkan for).

Unfortunately I couldn’t find a solution so workarounds only for now.

RetroArch seems to have several ways to limit the game’s speed. There’s Sync to Exact Content Framerate, Sync with Audio and Vsync. I don’t know which one is at fault but for ParaLLEl I found the following combination to work:

Vsync = OFF Sync to Exact Content FPS = OFF Sync With Audio = ON

Switching ON any of the others capped the framerate at about 40fps.

Anyway, try different combinations, as for instance with Citra I had to turn on Sync to Exact Content and leave the others off.