[nsp] Cisco 3524XL switching two networks with one network port

[Dave [Hawk-Systems]]

Cisco 3524XL
FE0/1 "port network" = ip block 192.168.1 coming down it (mac address 1 on other
end)
FE0/2 = ip block 192.168.2 coming down it (mac address 2 on other end)
FE0/3 -> FE0/12 are machines on the 192.168.1 block
FE0/13 -> FE0/24 are machines on the 192.168.2 block
IP Default Gateway set for 192.168.1.1 (datacenter switch out port FE0/1)
No VLANs configured (didn't think they were necessary since the 192.168.1 block
comes to us from one MAC address onto FE0/1, and the 192.168.2 block comes from
another MAC address onto FE0/2

we are seeing unusually low (lower than expected) traffic out FE0/2 (the
192.168.2 block) and I am wondering, since we don't have VLANs specified to
divide up the ports, that the switch is pushing traffic for both nets out FE0/1
because it is the only port with the "port network" attribute (since it doesn't
care much about the IP addresses) and/or the "IP Default Gateway" is out that
pipe?
Would that cause a speed degredation?

Thoughts or comments?

Dave