I have upgraded my Netgear router from an old "b" ver to "b/g". what surprised me is that my laptop wireless connection speed gone up from 1.2 meg on average to 6.4 meg. Every thing kept the same eg channel no etc. I would have upgraded earlier if I knew I would get so much improvement!!. However the wired connection for my desktop remained the the same.
The B to G runs the wireless at a greater speed, hence the speed improvement. The other wired (physical cble) will be running at the same speed, I presume around the same as the G wireless or better.