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

1.
tão lento quanto melaço, extremamente lento
extremely slow; moving or happening at a very low speed
:
•
The old computer runs as slow as molasses.
O computador antigo funciona tão lento quanto melaço.
•
Traffic was moving as slow as molasses on the highway.
O trânsito estava se movendo tão lento quanto melaço na rodovia.