CacheTOP holding more in RAM than it needs/should?

I’m using a cache for a very utilitarian use case of “pre-processing” some very large image frames and storing the result in a cacheTOP in order to wipe away the ram used in processing. I have the cache set to a size of 1, inactive, replacing single and it appears to eat twice the ram of a single frame of the data. Is this expected or a bug?

Attached tox is what I’m doing, hit the Reload to get the cached image, inside is a comparison of ram usages of a single frame and the cache.

highResLoader_forum.tox (2.1 KB)

I realize I can lock a null instead of caching, just didn’t want to deal with the onSave gymnastics and found this.