I was hoping I could use the cache sop to ram cache geometry in Houdini Engine in Maya. It doesn't seem to have any effect. Is there a way to get it to work?

How are you trying to use the Cache SOP? Are you trying to add the Cache SOP to the input, and expecting to see a performance gain? There's probably no performance gain here because Maya has to pass the input geometries to Houdini Engine every frame regardless of whether there's a Cache SOP or not.

Or are you using the Cache SOP in some other ways?

No I'm just caching what Houdini's doing, no Maya inputs.

I've done some more testing, the cache sop is having an effect, just nothing like I'd expect it to. I have an alembic file (in the asset) that normally plays at 1.9 fps (in both Houdini and Houdini Engine). When the cache sop is applied in Houdini it hits 90fps. In Houdini Engine in Maya it only increases it to 4fps.

Hm, I can't seem to reproduce the case where adding a Cache SOP after Alembic would speed up playback in Houdini. In all the tests that I've done, adding a Cache SOP after the Alembic SOP actually made playback significantly slower. This is a known viewport bug. What setup do you have that you're seeing a speed up from 1.9fps to 90fps?

Though in Maya, the cache SOP does seem to have an effect. I was able to get a speed up from 10fps to 20fps. But I don't have a valid Houdini case to compare this with.