5.0 Wireless Very Slow

Hi ..
Got my Laptop [HP Presario ze2000] up and running under 5.0.1 and the broadcom card working using FWCutter finally ...
But now the problem seems to be that the wireless connection is only running at around 8-10 mbps rather than the usual 45-54 under Windows ??? .. Hence it takes almost forever to get anything done on the internet .. when I 'ping' the router it takes approz 30-40 ms to get an echo and even longer to get an echo from other systems on my network
The Router is a Dlink 524 and the Wireless card is the Broadcom 4318 ..
If I boot up in 4.02 and use Ndiswrapper to setup Wireless the speed seems to be in the normal 45-54 Mbps ...[ note: I could not get the Wireless to work in 5.0.1 using Ndiswrapper ]
Any help would be greatly appreciated

thanks in advance
Wolf

8-10mbps is enough for internet and for downloading