well, when people ask me about usb network cards, I always say this:
"USB is for gamepads and scanners, network cards are for networks"
I say that, because the problems you are having are not uncommon with usb networks.
If they squeeze olives to get olive oil, how do they get baby oil?
As implied by CALV the USB ones are totally weak. You were probably better off before. Get a GOOD internal network card and you'd be set. I like PCI myself, but I'm lazy and fat. There are some who won't touch it if it aint ISA. Also pick a good one and don't listen to the fools who say that any old thing will do. I've found that precisely for ping reasons (for my games) you NEED a good NIC.
thats if the card will do 100, and if the card is fiber or cat5
how do you shoot the devil in the back? what happens if you miss? -verbal
"oh!..only 12mb per sec? wa..that is quite slow..how it suppose cope with 100mb? is it some kind of marketing tricks i didn't aware of?"
This can be done since 10mbps isn't quite enough to take full advatage of the 12mbps bandwidth. In order to realize the entire 2mbps more bandwidth you need to step up to the 100mbps standard. Pretty sad IMO, but it allows the shifty eyed a stab at some fool money.
My guess is that you suffer more from the high latency required to do the protocol hopping more than total bandwidth limitations of USB though, thus the better performance from the 10Mbps NIC.