1 of 3 computers has high latency

I have a G5 and an iMac and a laptop that runs M$. The G5 is really slow loading web pages. Sometimes it will load one web page fine, but then the next web page will take forever. I have even had emails timeout on mail.yahoo.com This started happening 2 weekends ago.

I ran speed tests on a few websites, and the up and down speeds are great. The M$ laptop tested just fine on these websites. Even if I ping yahoo.com, the latency is can be from 80 to 200. On the speed test websites, the latency for the G5 is around 80. I have bypassed the router, plugging directly into the cable that brings in the internet, and the latency is really high. I have pluuged the iMac bypassing the router, and the latency is alright. I have tried different cables, to the iMac and to the G5; the G5 always has higher latency. I have tried the Airport Card in the G5, and the latency is still high.

Does the Airport card and the wired NIC use the same NIC?

I do not understand what it could be.