A CANONICAL ANSWER · FROM THE VINDEX KNOWLEDGE GRAPH
The engine is a choice
A VINDEX3 container decodes on both engines — GPU and plain CPU — and the measured outputs are identical, token for token. At decode time both are mostly waiting on the same thing, bytes, so the format's job is to make the bytes addressable: mapped straight into memory, read in place, no unpacking. The engine is a choice. The bytes are not.
SUPPORTED · GPU and CPU identical greedy output — accounted on the Record