“Avg Net I/Os per Check” reports the average number of network I/Os (both sends and receives) per check for all Adaptive Server engine checks that took place during the sample interval.
The sp_configure parameter i/o polling process count specifies the maximum number of processes that Adaptive Server runs before the scheduler checks for disk and/or network I/O completions. Tuning i/o polling process count affects both the response time and throughput of Adaptive Server.
See the System Administration Guide.
If Adaptive Server engines check frequently, but retrieve network I/O infrequently, you can try reducing the frequency for network I/O checking.