It is throttled, although we’re still working out the exact details.
Practically, it’s not significantly more headroom than PICO-8 had because the screen is so much larger. You’ll have to use a low resolution screen mode if you want to do CPU-heavy things that wouldn’t fly in PICO-8.
Is that ballpark, or throttled for consistency? The FAQ has a "How Fast is the CPU?" item, but that just discusses being fast and faster than PICO-8.