Does spending from Orchard take less processor time than spending from Sapling?

I have an idea of the processor time required on my PC and on my phone when spending zcash in my Sapling pool. It is proportional to the number of inputs that go into the transaction, from what I can tell.

I read somewhere that Orchard is more processor friendly. I imagine it is still proportional to the number of inputs, but is it faster than spending from Sapling?

One question in particular I am pondering is whether the Trezor support for Orchard will have bearable performance. Will ZK-proof processing happen on the Trezor itself (bound to be super slow, I imagine) or can it safely offload that processing to the PC/phone for a faster experience? Or maybe Orchard is so fast that Trezor can handle it all internally.