If you want real LAN performance, use wired, esp. wired gigabit.
Don't get your hopes up about saturating the wireless marketing figures. Since you just can't do "54 Mb/s" or "108 Mb/s" actual data throughput with even full connection speeds over wireless, you're bound to see less than 100% network utilization -- typically much less, which is normal for wireless.
22 Mb/s is a good upper limit for standard 802.11g. If "108 Mb/s" actually doubles, then you'd hope for 44 Mb/s, but again note that the doubling is more hopeful than a practical guarantee.
Note also that wireless performance can vary a lot according to distance, obstructions, local conditions, time of day, wireless phones, microwaves, baby monitors, other wi-fi activity, etc., etc.
iperf (1.7) is a good tool for LAN measurements.
E.g.
server: iperf -s
client: iperf -c
server -l 64k -t 12 -i 3 -r
Here are some of my own wireless and wired figures for fun. I reduced the frequency to keep the length down in this post.
Wireless bridge, 802.11g, not optimal (i.e. I've measured better in the same configuration at different times), short to moderate distance, a couple of obstructions, wireless phones in proximity though not active:
F:\tools\bench\iperf>iperf -c 192.168.0.144 -l 64k -t 12 -r
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 8.00 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.0.144, TCP port 5001
TCP window size: 8.00 KByte (default)
------------------------------------------------------------
[816] local 192.168.0.141 port 16723 connected with 192.168.0.144 port 5001
[ ID] Interval Transfer Bandwidth
[816] 0.0-12.0 sec 20.9 MBytes 14.5 Mbits/sec
[852] local 192.168.0.141 port 5001 connected with 192.168.0.144 port 1273
[ ID] Interval Transfer Bandwidth
[852] 0.0-12.1 sec 20.1 MBytes 14.0 Mbits/sec
Wired gigabit, no qualifications needed:
F:\tools\bench\iperf>iperf -c 192.168.0.145 -l 64k -t 12 -r
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 8.00 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.0.145, TCP port 5001
TCP window size: 8.00 KByte (default)
------------------------------------------------------------
[816] local 192.168.0.141 port 16715 connected with 192.168.0.145 port 5001
[ ID] Interval Transfer Bandwidth
[816] 0.0-12.0 sec 1.32 GBytes 942 Mbits/sec
[784] local 192.168.0.141 port 5001 connected with 192.168.0.145 port 1104
[ ID] Interval Transfer Bandwidth
[784] 0.0-12.0 sec 1.32 GBytes 948 Mbits/sec