  We are developing a new readout board with a newer generation
field-programmable gate array (FPGA) and the 10-gigabit ethernet to improve the
performance and usability of the current readout board based on the 1-gigabit
Ethernet. In this new readout board, the SiTCP-XG network processor supporting
10-gigabit Ethernet was implemented. SiTCP is a network processor circuit
running on FPGA, and SiTCP-XG is the newly developed version of the SiTCP that
supports 10-gigabit Ethernet. Before developing the new board, we constructed a
prototype system using the Xilinx FPGA evaluation board KC705 to evaluate the
SiTCP-XG. This prototype system was tested with the SOI pixel detector, which
has 425,984 (column 832 x row 512 matrix) pixels and a pixel size of 17 x 17 um
at the synchrotron beamlines of the PhotonFactory (KEK). This was the first
test of the X-ray imaging for this system. The results showed that this system
worked stably with a transfer rate of 682 Mbps (equivalent to a frame rate of
100 fps, limited by detector operation parameters), and also worked stably with
a transfer rate of 2.4 Gbps (equivalent to 350 fps, the maximum rate limited by
the detector performance). These results suggest that the SiTCP-XG system has
sufficient transfer performance to cover the SOIPIX detector performance.
