Well, it's more than just for science.  We have some features coming which will require transferring 10s of KB from EC to AP relatively quickly, and we need to know whether the existing implementation is sufficient...

Here is some data for eve / kevin:

- Shipping kevin config (160 byte host command response, 3 MHz SPI) can achieve ~101 KB/s.
- This can be increased to ~229 KB/s if we bump our host command reply to 512 bytes (we can't easily do this on npcx5 due to the bitflip bug, but npcx7 should work).
- Shipping eve config (248 byte host command response, eSPI) can achieve ~167 KB/s.