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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  • lazybum131 - Tuesday, February 14, 2006 - link

    Actually, if you take into account the larger capacity battery on the T60, 56WHr compared 51 WHr, the T43 comes out ahead most of the time. The T60 has a 9.8% larger capacity battery, but with the fix it only comes out ahead 3.2%, 1.85%, 8.24% and 5.04%. Reply
  • Anand Lal Shimpi - Monday, February 13, 2006 - link

    I'm looking into this issue myself and I will have an updated Core Duo performance article in the coming weeks that will address this as well as many other items. I wouldn't use the ASUS notebooks to compare Napa to Sonoma, especially given the internal USB 2.0 camera. I am hoping to do a Lenovo based Napa vs. Sonoma comparison that will hopefully make things a lot clearer.

    Take care,
    Anand
    Reply
  • JarredWalton - Monday, February 13, 2006 - link

    I think that Napa allows a lower power setting, but you have to remember that two cores are still going to use more power than a single core when active. It might be interesting to see a test comparing Sonoma and Napa with the same CPU, as Dothan and Yonah both fix socket 479. There's also a question of the other peripherals, though: NIC, sound, screen, etc. all draw power. The newer Napa laptop from ASUS might have a better (re: brighter but more power hungry) LCD, for example, or a different HDD model. I don't know if they're strictly "identical" in other components, but a change of platform often involves other tweaks as well. Reply
  • NullSubroutine - Monday, February 13, 2006 - link

    Id be more apt to say that the increase of the FSB and the second additional core are more likely the cause, because I think they did make sure the Asus laptops were exactly the same. Reply
  • IntelUser2000 - Tuesday, February 14, 2006 - link

    quote:

    Id be more apt to say that the increase of the FSB and the second additional core are more likely the cause, because I think they did make sure the Asus laptops were exactly the same.


    Keep in mind that with laptops especially with power consumption there is so many variations to battery life problem. It could be that the implementation of the BIOS or voltage regulator is different across the two. Voltage regulator is said to be 5-10% of total power consumption, so differences in V-reg can make differences you are seeing.

    Look here: http://www.hardwarezone.com/articles/view.php?id=1...">http://www.hardwarezone.com/articles/view.php?id=1...

    Even with a faster CPU, MSI M635 with 1.8GHz Turion outperforms HP Compaq nx6125 with 2.0GHz Turion. It also gets better battery life even with X700.

    I think 5% difference is well within the range.
    Reply
  • huges84 - Monday, February 13, 2006 - link

    Doh! I completely forgot about the dual vs single core issue. And your other points are valid as well. Reply
  • kmmatney - Monday, February 13, 2006 - link

    Looks like I'll be using my old USB 1.1 mouse when I travel from now on. Reply
  • huges84 - Monday, February 13, 2006 - link

    Yeah, a lot of people will be checking what version of USB their mouses are. I know I will be. Reply
  • Saist - Monday, February 13, 2006 - link

    In reguards to THG, I was surprised to see a link as well.

    In reguards to AMD systems, I have a Turion on hand from Fujitsu (Lifebook S2000) and have been unable to duplicate the power loss from a default state with either a USB 2.0 external DVD drive, or a USB 2.0 Plextore ConvertX device.

    I was also surprised to see that Anandtech didn't test any Turion systems themsevles in the article. But, having tested 2 Centrino systems of my own (one from Sager, the other from Dell), in addition to the Fujitsu, yes, it is time consuming.
    Reply
  • Zebo - Monday, February 13, 2006 - link

    Anand refuses to test new turions similarly equiped.. don't know why I've emailed him never heard back. Go to laptop logic. Reply

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