The graphic shows the possible refresh rates and transfer times depending on the number of channels
Channels[USBP]: This is the size of datapackets on the USB-bus, telling how many channels are transfered to uDMX at a time. In the software uDMX-Artnet this value can be set from 1 to 512.
Refresh 512 [Hz]: The maximum refresh rate when values of all 512 channels change at a time.
Refresh[Hz]: The maximum refresh rate when only a block of USBP channels change at a time.
Time[microsec]: Time that is needed to transfer USBP channels to uDMX hardware.
Time 512 [microsec]: Time that is needed to transfer 512 channels to uDMX hardware with a packetsize of USBP.
When using a packetsize USBP of 256 it is possible to achive a refresh rate of 30 Hz when only 256 channels change at a time. Using 512 channels this reduces to the half (15Hz).
These refresh rates can only be achieved, when the DMX-software transfers the changing values in packets of USBP bytes. If the software transfers the bytes of each channel separately the refesh rate is reduced as if USBP would be 1.