Wireless not working correctly

I have a laptop in which has an excellent signal -38db and no noise-90, SNR 55. I am practically on top of the router and my speed keeps changing and sometimes drops. I am at 54 then 36 , 18 then back up to 54mbps. While this is happening I monitor the signal and noise but they are always great. I have disables WZC and have tried many different routers to see if this is the problem. I am at a loss. Is there anyone with some good knowledge to help me with this. I am using a Gateway 7405gx notebook.
Thank You
Sal

I ran ethereal and this is my results after 1 hour tcp 87.2% udp 9.2% arp 3.6%. This does not sound correct what should I do?

Are there any other wireless networks around? Does your noise ever move from -90? (some cards can't measure noise so it's usually fixed)
Any cordless phones around?
Have you tried using another channel?
Are you using the latest firmware/drivers?

Hi there

In just about all of the situations that I have seen with this problem it is due to interference. As Noodles said check for 2.4GHz cordless phones, old Blue tooth devices, microwave ovens, wireless speakers and other wireless networks etc. Have you tried different channels, alot of AP's default to channel 6, try 1 or 11 and see if it is any better. You can use Netstumbler to check for other networks. But also, it could just as well be a faulty client adaptor in your notebook.

Good luck
Dale