Ethernet problems when CPU is not being used

ajh499 · 05-18-2009, 03:34 AM

Hello everyone,

I hope someone can help me with a very strange problem.

I have two brand new HP EliteBook 8730w laptops, with quad core processors. One is running Vista, the other has XP on it.

The problem I am having is that when streaming data packets over a TCP connection from either an embedded device or from another computer running some test software, the laptop either loses some of the data, or it arrives late after a number of retries. This is using the built in Intel gigabit ethernet card, not the wireless.

I'm seeing errors in the received column if I do a netstat -e. And I see "Packets received discarded" in Windows Performance Monitor.

The really strange thing is that if I run something other than the data receiver program, either a bit of test software written by me, or something like Prime95, so that the CPU is loaded, suddenly the data errors stop and all the packets are received correctly.

It doesn't matter which of the two laptops I use as the receiver, both have the same problem. I've tried different network drivers and made sure all other drivers are up to date. The laptops already came with the most up to date bios.

I've even tried using ExpressCard and USB network adapters instead of the built in Intel card with no luck.

Has anyone ever seen anything like this

Any help would be greatly appreciated.

Alex

**johnwill** · 05-18-2009, 02:45 PM

I'd say the test software is either configured incorrectly or has some issues.

ajh499 · 05-19-2009, 02:33 AM

Quote:

Originally Posted by johnwill

I'd say the test software is either configured incorrectly or has some issues.

No, I don't think that's the problem as there are three different ways to demonstrate this problem.

Run the full suite of software we are developing receiving data from an embedded device
Run a test program on the laptop receiving data from a test program on another computer
Use a third party network test program such as PerformaceTest 7 from Passmark.com

While running these tests, I have had the computers connected back to back or through a switch, it makes no difference.

I'm very confused

Alex

**johnwill** · 05-19-2009, 02:02 PM

I don't really have any ideas, this is obviously something that I'd have to be a lot closer to try to diagnose.

ajh499 · 05-20-2009, 01:34 AM

Quote:

Originally Posted by johnwill

I don't really have any ideas, this is obviously something that I'd have to be a lot closer to try to diagnose.

Understood, it is a very bizzare problem.

No one else has any suggestions as to what might be causing an effect like this?

I did wonder if it might be related to speedstep, but there's no way to turn it off on these laptops so I can't test that idea.

ajh499 · 06-01-2009, 04:08 AM

Anyone?

Of all the networking gurus around here, someone must have some ideas. Even if it is just things that I could check.

Alex

05-18-2009, 03:34 AM	#1 (permalink)
ajh499 Registered User Join Date: May 2009 Posts: 4 OS: Many	Ethernet problems when CPU is not being used Hello everyone, I hope someone can help me with a very strange problem. I have two brand new HP EliteBook 8730w laptops, with quad core processors. One is running Vista, the other has XP on it. The problem I am having is that when streaming data packets over a TCP connection from either an embedded device or from another computer running some test software, the laptop either loses some of the data, or it arrives late after a number of retries. This is using the built in Intel gigabit ethernet card, not the wireless. I'm seeing errors in the received column if I do a netstat -e. And I see "Packets received discarded" in Windows Performance Monitor. The really strange thing is that if I run something other than the data receiver program, either a bit of test software written by me, or something like Prime95, so that the CPU is loaded, suddenly the data errors stop and all the packets are received correctly. It doesn't matter which of the two laptops I use as the receiver, both have the same problem. I've tried different network drivers and made sure all other drivers are up to date. The laptops already came with the most up to date bios. I've even tried using ExpressCard and USB network adapters instead of the built in Intel card with no luck. Has anyone ever seen anything like this Any help would be greatly appreciated. Alex

05-18-2009, 02:45 PM	#2 (permalink)
johnwill Manager, Networking Forums Join Date: Sep 2002 Location: S.E. Pennsylvania, US Posts: 41,940 OS: Windows 7, XP-Pro, Vista, Linux Blog Entries: 1	Re: Ethernet problems when CPU is not being used I'd say the test software is either configured incorrectly or has some issues. __________________ If TSF has helped you, Tell us about it! or Donate to help keep the site up! Microsoft MVP - Windows Desktop Experience

05-19-2009, 02:02 PM	#4 (permalink)
johnwill Manager, Networking Forums Join Date: Sep 2002 Location: S.E. Pennsylvania, US Posts: 41,940 OS: Windows 7, XP-Pro, Vista, Linux Blog Entries: 1	Re: Ethernet problems when CPU is not being used I don't really have any ideas, this is obviously something that I'd have to be a lot closer to try to diagnose. __________________ If TSF has helped you, Tell us about it! or Donate to help keep the site up! Microsoft MVP - Windows Desktop Experience

06-01-2009, 04:08 AM	#6 (permalink)
ajh499 Registered User Join Date: May 2009 Posts: 4 OS: Many	Re: Ethernet problems when CPU is not being used Anyone? Of all the networking gurus around here, someone must have some ideas. Even if it is just things that I could check. Alex