Longhorn 4074 fries my CPU :-(

Well, I got that fantastic Dell Inspiron 8600c (Pentium M 2GHz, 2 GB RAM, ATI Mobility Radeon 9600 Pro Turbo w/ 128MB video memory) which runs XP in Virtual PC faster than most of my other machines do on hardware, so I thought this would be the perfect machine for the WinHEC Longhorn build, incl. DWM and such. Imagine my surprise when (after the usual struggle with drivers) I noticed that it was slow and jerky. Disabled WinFS (the obvious suspect :-), no change. Taskmanager then revealed what was happening:


Whatever process I am launching, total CPU usage always sums up to >99%, there seems to be no idle task. The performance tab shows more information:


So most of the CPU cycles are used by the kernel. WTH is happening here? I'm clueless... Any ideas appreciated 🙂

(Interestingly, one of my other machines also happens to be a 8600, with Pentium M 1.5GHz, and there, 4074 runs perfectly well. So I'm puzzled even more.)

Comments (15)
  1. a. says:

    this picture shows that actually the taskmanager eats up your cpu time ;]

  2. FrankPr says:

    Ahh, actually no, this is just a coincidence. The most active tasks are sharing the 100% CPU usage among them:

    <img src="http://www.winisp.net/fprengel/images/taskman2.jpg"&gt;

  3. Simon says:

    Graphics drivers? Try changing to another driver…?

    Disk interface drivers? Try turning the swapfile off temporarily and see if there’s any improvement. Is there disk thrashing?

    I dunno, I don’t have longhorn (damn msdn universal price being £2000+), but it looks like a driver is stuffed/needs changing/needs avoiding.

  4. travis says:

    Try throwing Seti@Home on there, see if it’ll be a virtual System Idle Process. Plus, on a machine like that, it’d be a shame to waste all those CPU cycles 😉

  5. art says:

    install the virtual machine addons

  6. Adam Hill says:

    See if the Winterals Process Explorer will run on LH. It will break out/sort CPU times by process.

    At least that will narrow it down.

  7. FrankPr says:

    Simon: Thanks for this great suggestion – yes, it seems to be a driver running amok. Let’s see if I can hunt him down…

    Art: I’m not running this in a VPC. Makes no sense if you want to see Avalon + DWM in its full beauty 🙂

    Adam: You mean Sysinternals? I’ll give it a try, thanks.

  8. FrankPr says:

    Ahh, just found out (thanks to Process Explorer) that I have

    %DPC Time > 90


    Deferred Procedure Calls. How do I find out which driver is causing this???

  9. FrankPr says:

    Hah! Started disabling devices in device manager, and just the second attempt was successful – my Broadcom 440x 10/100 Integrated Controller was the bad boy! So I’m gonna find a more suitable driver.

    Thanks a lot to everyone who shared their suggestions – I highly appreciate it!

  10. Legend says:

    Yeah I tried it also on my Inspiron 8600, and I just can’t get the Broadcom 440x 10/100 Controller working.. I tried the driver from the Dell Support site as well as the WinXP and Win2k3 driver from the Broadcom site, all with no success. The strange thing is that it doesn’t even seem to be that the driver is not signed, it just doesn’t show any available models when I try to add a network adapter and use the driver’s inf file. My Dell Truemobile 1300 Wireless adapter works fine, though.. Any ideas on how to get it working without having to use an external network PCMCIA card?

  11. FrankPr says:

    Legend: Welcome to the club 🙂

    I guess this Broadcom thing is highly dependent on the overall HW config (chipset etc.) of the machine – as I wrote, I have another 8600 where the same driver works flawlessly. I’ll go with a PC card network adapter for this build. I could maybe ask the kernel dev guys in Redmond, but I think it’s no use bothering them with such issues of an early alpha build, since they’re already occupied with the next milestones. Let’s be happy that this works pretty well at all.

  12. Legend says:

    I remember back in the days of the early Whistler betas, when lots of drivers were still missing and some guys even got a soundblaster driver working when no available driver was making a sound 🙂 I guess things like the broadcom driver issue right now are just a shadow of the storm that is to come, when they start enforcing the new Longhorn driver model and even most of the XP drivers won’t work anymore.

    I always loved playing around with those builds, and to a certain degree I try to get some things working, but I don’t have a problem waiting for the next build when it will work (and other things break…) 🙂

  13. mike says:

    yea this build (installed normally) seems faster and more stable, but doesnt work with any of my motherboard drivers. Most of them install (manually), but then it gives me errors that the device failed to start. Guess ill have to wait for another build.

  14. cr3ative.net says:

    This website cured the problem for me; it lists all unneeded or CPu heavy lh4074 features.


  15. nuju castle says:

    i have a asus kav delux i was runnning xp 64 and all the 64 drivers i had worked but in longhorn the only one to work is the nvida 64 driver can anyone tell me what card that i could get to make this think work or a driver for my 3com 3c940 for longhorn or how to write my own

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