I just got the D-Link DWL-G510 (I have revision C) and was getting crappy performance, such as high ping, lag spikes and connection dropping. D-Link are rubbish and for the last 2 years left their drivers at version 1. Since the DWL-G510 uses the Ralink RT61 chipset and Ralink do upgrade their drivers, you can download and use their drivers
PCI/mPCI/CB(RT256x/RT266x).
Using the D-Link drivers I was getting a 4ms ping to the router, and occasionally a 1500-2000ms ping spike.
Using the Ralink drivers I am now getting a <1ms ping to the router and no spikes.
In both cases I was not using Wireless Zero Configuration which apparently improves performance.
