Problem #3 - The fix doesn't always work

We've proved the problem exists, confirmed that it affects more than just Core Duo systems, and have posted Microsoft's solution - so why even bother with an article? 

The problem is that the fix isn't exactly perfect yet.  The biggest problem that we've seen thus far is that while applying the fix gives you back the vast majority of your lost battery life, it won't remain active coming out of suspend.  Once you apply the fix, you are set for as long as that key remains in your registry.  However, if you put your notebook into stand-by, and when it comes out of stand-by, the fix will no longer be active.  The only solution at this point is to reboot your system, which causes the registry to be re-read, and the fix will continue to work normally. 

We confirmed this by once again looking at Perfmon with the C3 residence extension:

The first vertical line (orange) indicates the system going into stand-by, and the second vertical line (green) indicates the system coming out of stand-by. Once the system wakes up, it eventually initializes the asynchronous scheduler again and the CPU is no longer able to enter its lower power states.

While the current workaround is better than nothing, it's still not completely resolved.  We still need a real fix from Microsoft. 

The Results

While we've already proved that the bug is platform independent, as well as showcased that the fix does work (somewhat), below we have data to show you the potential impact of the bug and what you gain back by implementing the fix on each of the five notebooks that we tested.

First up is the Napa based ASUS W5F; keep in mind that this platform features an integrated USB 2.0 camera, so the asynchronous scheduler is active even with no external USB devices connected:

 ASUS W5F (Napa/Core Duo) Nothing Connected  USB Drive (USB 2.0)  External HDD (USB 2.0)  Mouse (USB 1.0)
Normal 219 205 214 216
With Fix 264 249 255 250

You can see that the fix gives you back a good deal of your battery life.  Keep in mind that the run-to-run variation of Mobile Mark 2005's Reader 2002SE test can be in the 3 - 5% range, so smaller differences should be ignored. Note the gain in battery life in the Northing Connected and Mouse (USB 1.0) columns. These gains are completely because of the integrated USB 2.0 camera.

While we're on ASUS, let's look at their Sonoma based W5A, also featuring an integrated USB 2.0 camera:

 ASUS W5A (Sonoma/Pentium M) Nothing Connected  USB Drive (USB 2.0)  External HDD (USB 2.0)
Normal 204 199 218
With Fix 273 260 268

As you'd expect, the W5A behaves very similarly to the W5F.  With the default (Nothing Connected) configuration receiving a huge increase in battery life after the fix was applied, you can see why the two ASUS notebooks are not an ideal test platform for measuring the impact of this bug. 

We also tested the Dell Inspiron E1705:

 Dell Inspiron E1705 (Napa/Core Duo) Nothing Connected  USB Drive (USB 2.0)  External HDD (USB 2.0)
Normal 154 130 133
With Fix 155 135 137

Interestingly enough, the E1705 doesn't actually gain all that much battery life from the fix.  We're still working on finding out why this is the case. For what it's worth, the E1705 has an integrated USB 2.0 hub that, like the ASUS systems and their integrated camera, complicates the issue.  A lot of this problem may be up to the aggressiveness of the power management designed by the notebook maker, but we'll be working with Dell on our final review of the E1705 to figure out exactly what's going on here. 

The final pair of notebooks that we compared are the Lenovo T60 and T43, the "cleanest" of the five in that they do not have any integrated USB 2.0 devices.  First up, the T60:

 Lenovo T60 (Napa/Core Duo) Nothing Connected  USB Drive (USB 2.0)  External HDD (USB 2.0)  Mouse (USB 1.0)
Normal 286 235 245 272
With Fix 290 275 289 271

The T60 behaves exactly as you would expect it to, with the notebook getting back virtually all of its battery life when paired with the External HDD with the fix applied.  We don't know why the Inspiron didn't do the same, but since the ASUS and Dell systems both featured integrated USB 2.0 devices, we can't really predict how they are supposed to react. 

The T43 also behaves as expected:

 Lenovo T43 (Sonoma/Pentium M) Nothing Connected  USB Drive (USB 2.0)  External HDD (USB 2.0)  Mouse (USB 1.0)
Normal 276 201 210 263
With Fix 281 270 267 258
Problem #2 - Disabling a USB device doesn't work Final Words
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  • mayurgala - Thursday, June 22, 2006 - link

    Hi,

    as we saw tht MS has come with a registry fix which gets off once the machine comes out of the standby mode.... SO y cant we use hibernate it will just consume some more hard drive space :)

    Hibernation vs Standby Mode are very similar and people tend to confuse the differences. Standby basically turns off power consuming components like the hard disks and monitor. It switches the computer to a low power state. Its much like a warm boot. Any contents of memory and unsaved desktop settings are lost. Hibernation saves state information by writing a hibernation file which contains the contents of memory and is thus the same size as total RAM. This is a snapshot of active memory. When you turn your PC back on, the state, including which applications are running (desktop) and the memory contents are restored to RAM and voila! - you are back to where you were when Hibernation mode started. The restoration of state can take place in 5 minutes, 5 hours, 5 days, 5 weeks, ....
    Hibernation is only available if your system is ACPI-compatible. If it is not, the Hibernation tab will be missing and you will have an APM tab instead. To enable Hibernation mode as one of your Shutdown options:
    Reply
  • V00D00 - Thursday, February 16, 2006 - link

    The link to the microsoft kb article is bad, it takes you here:
    file://localhost/kb/256986

    It's supposed to be:
    https://premier.microsoft.com/kb/256986/">https://premier.microsoft.com/kb/256986/
    Reply
  • IntelUser2000 - Wednesday, February 15, 2006 - link

    Tomshardware: http://www.tgdaily.com/2006/02/14/microsoft_to_rel...">http://www.tgdaily.com/2006/02/14/micro...e_patch_...

    Anandtech: http://www.anandtech.com/mobile/showdoc.aspx?i=269...">http://www.anandtech.com/mobile/showdoc.aspx?i=269...



    Can anyone tell me why both systems with EXACTLY the same configuration AND drivers behave differently in terms of USB 2.0 power drain problem??

    If Anandtech is right about the fact that since Asus W5A/W5F has integrated USB 2.0 camera, connecting a external USB 2.0 device shouldn't affect battery life since it already has USB 2.0 device via camera installed.

    However, it does not. While Anandtech's results are consistent with THEIR own conclusions that disabling the device doesn't remove the problem, the only way is to physically remove it, it doesn't show for Tomshardware results.

    Summarizing the differences:
    Tomshardware
    1. With no external devices connected, Core Duo laptop has SIGNIFICANT battery life advantage over Pentium M
    2. Core Duo laptop loses significant battery life when external USB 2.0 device is connected
    3. Battery life AFTER the LOSS is STILL pretty much equal to Pentium M laptop
    4. Pentium M laptop loses very insignificant amount of battery life with USB 2.0 device connected
    5. Core Duo laptop AFTER THE PATCH GAINS significant battery life close to the result with no external devices connected, now the difference between CONNECTED and UNCONNECTED is within expectations
    6. Pentium M laptop ALSO gains battery life after the patch, but much less significant then Core Duo laptop

    Anandtech
    1. Core Duo laptop has very little battery life advantage over Pentium M
    2. Core Duo laptop loses insignificant battery life when USB 2.0 device is connected
    3. Battery life after the loss is pretty much equal to Pentium M
    4. Pentium M laptop loses insignificant battery life with external USB 2.0 device connected
    5. Core Duo laptop AFTER THE PATCH gains significant amount of battery life
    6. Pentium M laptop ALSO gains SIGNIFICANT amount of battery life.


    Anand??? Tom??? Who the hell is wrong here?? Will you two sites stop bashing each other who has more "professional" journalism and cooperate, see what's wrong?? So umm, MAYBE WE KNOW WHY THERE IS A DIFFERENCE??!!
    Reply
  • clnee55 - Wednesday, February 15, 2006 - link

    Don't know who is right and who is wrong but at least THG is more consistent. Anand's conclusions are contradictary. Ex: 2 and 5. If the CoreDuo loses insignificant when USB2 is connected, how can it gain significant after the patch. Same contradiction between 4 and 6

    1. Core Duo laptop has very little battery life advantage over Pentium M
    2. Core Duo laptop loses insignificant battery life when USB 2.0 device is connected
    3. Battery life after the loss is pretty much equal to Pentium M
    4. Pentium M laptop loses insignificant battery life with external USB 2.0 device connected
    5. Core Duo laptop AFTER THE PATCH gains significant amount of battery life
    6. Pentium M laptop ALSO gains SIGNIFICANT amount of battery life
    Reply
  • NullSubroutine - Wednesday, February 15, 2006 - link

    i dont think his summary was accurate to what anand what saying. which was under all circumstances usb 2.0 makes Pentium M and Core Duo lose battery power due to the issue with windows.

    thg diabled the camera THOUGH the bios, where as i believe anand did it inside windows.
    Reply
  • tyildirim - Wednesday, February 15, 2006 - link

    And what about how swap cd/dvd bays alot of IBM's dell's has (also my d600) a removable internal cd writer in the task bar is si seems to be an usb device added to the system which I can "safelym remove" etc. so will it also affects battery life? quite confused now? Reply
  • hardcandy2 - Wednesday, February 15, 2006 - link

    A similiar thing happens to the Dell Axim x50v with WM 2005, a battery drain takes place, due to a "file manager"(?) that keeps running. Saw it posted on www.aximsite.com a while back. Going by memory here which is not the best this AM. Reply
  • paulsiu - Wednesday, February 15, 2006 - link

    Ok, the driver architecture is likely to be different, but does the problem occur under Linux? Reply
  • NullSubroutine - Wednesday, February 15, 2006 - link

    i just read toms update, anand is by far better written, more informative, and used better methodoligy. go anand! Reply
  • mark1 - Tuesday, February 14, 2006 - link

    Mark Twain had a saying, pardon my paraphrase, that a lie makes it halfway around the world before the truth gets its shoes on.

    THG has zero credibility. Their smug little article is still up and my bet is will stay up uncorrected so all the AMD fanboys can chortle about mighty Intel stumbling.

    Turns out, THG tried a little too hard this time. So they found 'dirt'; turns out the same phenomenon afflicts all Sonoma product, too.

    Before you know it, the story will have morphed into: plug any USB into a core duo and it drains the battery instantly. Heck, I was just at a retail store last weekend and was warned by a "salesman" that Duos have a battery drain problem. I asked him if he reads Tom's Hardware a lot - he wasn't ready for that. Or for that fact that I said it is a USB implementation, really nothing to do with the Centrino product. But the next 50 customers will get the same 1/2 truth. And all 1/2 truths are is lies.
    Reply

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