["Alan D." <frayed@xxxxxxxxxx>]

Hello everyone!

I have a bit of a networking issue that I'm hoping some of you will be able to help me with, since I've given it up as a lost cause myself!

Around September 2006 I built myself a brand new machine.  AMD Athlon X2 4800+ (socket 939),  ECS NForce4 mobo, 2 GB 
G.Skill DDR400 memory in dual channel, 2 Seagate 80 GB SATA300 drives (striped), and a GeForce 7900GT 256mb.  Along with it I purchased a copy of Windows XP Professional X64.  Paranoid as I am about defective components the system was tested using Prime95, memtest86+, and 3dmark and appeared to be a rock solid build.  However I immediately noted that when playing Ultima Online (a really old mmo) that there would be some new inexplicable lag spikes, where I would just freeze up in game for anywhere from 6-20 seconds; I didn't *notice* any problems with any other games so I wrote it off as some sort of incompatibility between UO and XP X64 and went about my business.

Months later I fineally realized that I was actually having lag spikes in other games, the only difference was those games didn't completely freeze me in place when a lag spike would occur.  Using Wireshark I discovered that what is happening is at some point a packet is lost and then resent as it should be, but following this there is what I can only describe as a "TCP DUP ACK" storm, where the same ACK is sent 10-200 times over a period of several seconds that coincides precisely with the lag events experienced in games.

The following is a list of things I have tried so far to determine the problem:

1) Replaced ethernet cable
2) Installed a Realtek 8139 NIC & disabled onboard NForce4 NIC
3) Replaced PIX 501 with a Windows 2000 RRAS server
4) Connected my PC directly to the modem (other systems in my house work fine)
5) Complete reformat and reinstallation of latest drivers for all hardware
6) Replaced motherboard with an MSI Neo4
 

So far I have had no luck whatesoever.  Someone please save me!


Thanks in Advance,

Alan