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Interface Transfer Rates

Transfer rates depend on a number of factors, including the device accessed the type of transfer, and cycle usage.

The table below includes typical transfer rates for the Optibit and USB interfaces at a 50% cycle usage with RP/RX and RZ devices.

Interface Transfer Type RP RX RZ
PO5/PO5e/FO5 Read 1.5 4.0 8.0
Write 1.0 1.0 8.0
UZ3 Read NS NS 6.0 *
Write NS NS 6.0 *
UZ2 Read 1.5 1.5 NS
Write 1.0 1.0 NS

Transfer rates are in MB/s. NS: Not Supported

* UZ3 transfer rates are highly dependent on the specs of the computer.

Because of the overhead required to poll the hardware or run single commands with the USB interface, users should be aware of the following relationships when performing small data transfers with the UZ2.

Interface Transfer Type RP/RX
UZ2 Snippet Transfers (~100) 0.3 MB/s
Single Commands 1000 Commands/s

Cycle Usage and Large Transfers

The following graphs show how the cycle usage affects the transfer rate for large transfers with the Optibit, Gigabit, and USB 2.0 interfaces with an RX device. The data was collected using a buffer size of 1,000,000 for the Read Tag and Write Tag commands. The transfer rates were tested using both the RP2.1 (a single processor device) and only the main processor of an RX6 and using circuits generating cycle usages of 5, 25, and 50 percent.