Here again, I think it's your network. Is there anything else on your network, or is it just a TwinStore and C15? That just doesn't make sense. No reason that a cat5e cannot pass a high res file.

Primary: MD600, MS200 (SpeakerLink to AES), Trinnov ST-2, Ayre V6-xe, Salk SS8 3x LRC.
Secondary: MC600 (whole house).
Zone one: 568.2, G57, MS200, Spatial Hologram M2SE.
Zone 2-6 (Awaiting assignment).