Pixelated HD Content?

I've posted this on the weaKnees support forum and thought I'd post it here to see other opinions...

Hi all,

In 2013 I purchased a Roamio Pro from weaKnees upgraded to 4TB. I can't say whether it's exhibited this behavior since new, but it seems to "pixelate" recorded HD content. I have tested the following:

Recorded HD TV programming (Bachelorette): Pixelates
Recorded HD HBO series (Game of Thrones): Pixelates
Recorded HD Movie (Spy, recorded via HBO): Pixelates
Recorded SD Movie (Road House, recorded via HBO): Does not pixelate
Streamed HD Movie (Amazon): Does not pixelate
BluRay Disc: Does not pixelate

The more intense the on screen "action" the worse the pixelation is. For example, Transformers recorded via HBO was almost unwatchable during intense actions scenes, where the slower scenes were ok.

Would I be on base to suspect that the culprit is the hard drives not being fast enough to supply the needed data for intense HD scene display? If it was a memory or other Roamio electronics issue I would think I would see the pixelation in streamed content, and that doesn't seem to be happening.

Thoughts?

Chris