(as) slow as molasses
US /əz sloʊ əz məˈlæsɪz/
UK /əz sloʊ əz məˈlæsɪz/

1.
lento come la melassa, lentissimo
extremely slow; moving or happening at a very low speed
:
•
The old computer runs as slow as molasses.
Il vecchio computer è lento come la melassa.
•
Traffic was moving as slow as molasses on the highway.
Il traffico si muoveva lento come la melassa sull'autostrada.