Is all internal processing now at a higher rate, ie a processor would currently upsample 44k input to 88k and all internal processing would take place at that. I assume that in light of the time based limitations that internally, 88/96 is no longer fast enough?

Don't know if same internal upsampling applied to 818.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).