Back in the early 90s, memory was quite expensive. Especially
fast Cache Memory was hard to get at all.
All of a sudden boards appeared and although having the cache sockets populated, still
being quite cheap.
The only mysterios thing was, that these boards were damn slow!
The german magazine c't revealed, that the Cache-Chips on the boards actually were empty crap.
A few hints for discovering faked cache:
Cache chips were soldered in.
No jumpers for cache configuration (or fixed).
WRITE-BACK being printed on them
Later the WRITE-BACK was replaced my some better (more real) looking printing.