|4 Mbps is not even 1/4 of the rated bandwidth of a G interface (54 Mbps). You should be able to achieve 54 Mbps between two laptops in ad-hoc mode. If it were me, I'd test.|
First, connect A and B (only) in ad-hoc.......what's the bandwidth.
Then connect A and C (only) and test
Then B and C.
Bandwidth should be consistent in all 3 cases. If it's not, then you may have some issues with the interface(s) and the above testing would help you isolate which interface is the problem (ie: the problem will follow the bad interface)
I am using this mickey mouse setup to use some never used network cards rather than piling new ones
Again, as per my initial response, I repeat, "Buy a wireless capable SOHO Router and create a WLAN on it and join your clients to it"
This allows you to create an actual WLAN (as vs. the ad-hoc mickeymouse solution) and then connect the laptops to it individually.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.