What’s Fixed In SP1

Bug fixes are a big part of any Microsoft service pack, but not just for the bugs being fixed specifically by the service pack. Microsoft has released numerous hotfixes since Vista launched, correcting a number of issues declared significant enough that they need to be fixed before the next service pack, but minor enough that they’re not worth a full deployment and the kind of massive regression testing that entails. The result is that there are a number hotfixes already out that can potentially fix specific issues certain users are having, but because they aren’t well-tested they’re instead well-hidden with only a small number of users with extreme problems usually getting their hands on any given hotfix. Now that a service pack has arrived, Microsoft has rolled up all of these hotfixes into the service pack, in essence approving them for wide release and full support.

Among the 24 pages(!) of hotfixes that have been rolled into Vista SP1 are favorites such as the virtual address space fix and a fix for a conflict with NVIDIA’s USB controller and >2GB of RAM. Other additions include fixes for ejecting iPods, a fix for HybridSLI/HybridCrossfire (which is why the launch of these technologies is tied to SP1), and a fix for AMD Barcelona processors causing system reboots during Windows installations. While we could rattle off the entire 24 page list of hotfixes, the important thing to note here is that there are a number of small issues that have been “fixed” prior to SP1 but are only now being widely corrected. We’re going to spend most of our time going over the biggest and most noticeable fixes in SP1, but please keep in mind there are many more things addressed in this service pack than what we’re looking at today or are listed in Microsoft’s consumer-level product literature.

Among the most significant fixes to Vista in SP1 is Microsoft's work on further refining the User Account Control (UAC) prompts of Vista. Even after already being scaled down between the betas and Vista’s launch, these prompts are still rather prolific at times. An adjustment to the folder creation is the most prominently touted of these fixes, with the number of folder creation prompts (when creating a folder in a protected location) falling from four to one. Microsoft doesn’t list any further reductions in UAC dialogs, but as far as anecdotal evidence is concerned it certainly feels like they’ve done a bit more than that. This won’t change the public perception of UAC (or Apple jokes on the subject), but any reduction is welcome and perhaps will stem the tide of Vista users who are completely turning off this critical system feature.

Another significant fix appearing in SP1 is a partial resolution to the conflict between the MultiMedia Class Scheduler Service and networking. As we’ve talked about the issue a bit before, the Vista audio stack is now in user space, which has lead to a change in how it operates. MMCSS boosts the priority of multimedia processes to real-time levels so that lower-priority processes can’t interrupt multimedia playback. During this time many other operations are interrupted or delayed so that they do not themselves interrupt the audio stack. One area that is dialed back involves the network interfaces, which are limited to 10k packets per second as a precaution.

For SP1 we were hoping for a complete overhaul of the MMCSS so that it ceased adversely affecting network performance, unfortunately what we’re getting is something about mid-way towards that. With SP1 it is now possible to control the amount of network throttling that MMCSS does, which means that throttling hasn’t been removed completely nor has it even been adjusted as far as the defaults are concerned. A quick test with Microsoft’s NTttcp tool shows the throttling level remains the same post-SP1 as it was pre-SP1 (roughly 70Mbps on a 1000Mb connection), which means SP1 will not be bringing any immediate relief. Furthermore there’s no GUI component (or real documentation) for this tweak, so users will be left to directly modifying the registry, a very uninviting situation.

What we do know is that this tweak only affects network receive performance, with a key apparently dictating the maximum percentage of the amount of network traffic allowed while the MMCSS is actively working. The key:

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\NetworkThrottlingIndex

...defaults to 10 (for 10%) and can be adjusted to between 1 and 100, with the system requiring a reboot between adjustments. We did some quick testing with this key and were easily able to set it to 70%, which got us around 550Mbps of bandwidth through NTttcp, and we probably could have gone higher - especially on multi-core platforms.

Default throttling (top) and throttling with an index value of 70 (bottom)

While this is a solution to the MMCSS throttling issue, it’s not a good solution. The default value still makes for rather anemic performance on gigabit networks and the nature of the solution means that there is no single correct value to use to maximize network performance while not interrupting the audio stack; the highest value is highly dependent on processor performance. As a result power users wanting to correct this deficiency will have to a lot of experimenting on their own to find the highest value their system can tolerate without affecting multimedia playback. Had this value at least been auto-sensing we wouldn’t be so disappointed in Microsoft, but at the end of the day this isn’t a great solution. We’ll fully admit the problem will only affect a small number of users (those with gigabit networks who need high network performance while using multimedia applications), but then we’re exactly that kind of user.

For what it’s worth, we did inadvertently discover that the MMCSS throttling process doesn’t engage when audio streams are using APIs other than WaveOut and DirectSound (i.e. aren’t directly routed through the user-mode audio stack). OpenAL and ASIO do not trigger throttling, which means it’s possible to have both unthrottled networking and proper multimedia playback under Vista, as long as there’s hardware present that can deal with these APIs. This may very well be good news for Creative Labs in particular, whose DirectSound-to-OpenAL “Alchemy” wrapper can be used to have DirectSound applications routed to OpenAL instead and preventing throttling.

NTttcp Performance

MMCSS Active
MMCSS Inactive
Vista RTM
Vista SP1 (Index 10)
Vista SP1 (Index 70)

Moving on, SP1 also introduces a few interesting fixes for the user experience. For anyone who has a system running a 32-bit version of Windows and 4GB of RAM, they will be well aware that in 32-bit mode not all of that RAM can be addressed, and that Windows reports the amount that can be addressed accordingly. With Vista SP1 Windows will now be reporting the amount of RAM in the system, and not the amount that can be addressed. The advantage of this is that it will reduce the number of computer owners thinking something is wrong because Windows doesn’t “see” all of their RAM; on the other hand this is clearly disadvantageous because they will no longer be informed that Windows in fact isn’t using all of their RAM, nor will there be an easy way any longer to tell how much RAM it is capable of using.

Another user experience change with SP1 is that password hints are no longer optional when accounts are being created. It turns out that OEMs were complaining to Microsoft that users were forgetting their passwords and had no easy way to recover control of their computer since the Administrator account is no longer active by default, so Microsoft has done something about it. Password hints are now mandatory for all user accounts so that forgetful users are less likely to forget their passwords. How that will affect people that then forget what their hints mean remains to be seen.

Index What’s Fixed In SP1, Cont


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  • Per Hansson - Wednesday, February 27, 2008 - link

    On the steam survey I think Windows 2003 64 bit is the same thing as XP x64, they share the exact same codebase (even serivcepack and hotfixes) It accounts for 0.73%

    But yes, I agree, XP x64 is a very nice OS
    It is IMO more stable than XP (it is afterall a server OS since it's based on Server 2003 x64)
  • Brunnis - Wednesday, February 27, 2008 - link

    Although more of academical interest, I'm sure I'm not alone in wanting to see the performance difference between an unpatched Vista RTM installation and Vista SP1.

    One pretty serious issue with Vista, that I can't seem to wrap my head around, is the folder types and how they're applied. They actually seem to be applied arbitrarily and without any sort of reason. They also sometimes seem to change without user interaction. I was hoping Vista would somehow address this, but it seems Microsoft is content with how it works.

    Otherwise I'm actually quite happy with Vista. I view SuperFetch as one of its most important features and one that actually makes Vista feel a good deal faster for general usage.
  • amandahugnkiss - Wednesday, February 27, 2008 - link

    in the article: http://www.dailytech.com/article.aspx?newsid=10781">http://www.dailytech.com/article.aspx?newsid=10781

    it was reported that MS was bricking PCs, I would have imagined you guys would have adressed that issue here. At least report if it was still an issue, was a false lead, or what the issue was and what the was that MS implemented.

    Any info on this topic you can share?
  • Ryan Smith - Wednesday, February 27, 2008 - link

    We mention it a bit on the last page; basically it looks like a very small number of computers having problems, but it's hard to cut through the echo chamber effect of the internet. AFAIK that update still hasn't been reinstated on Windows Update though.

    We haven't experienced the issues on any computers we own.
  • amandahugnkiss - Wednesday, February 27, 2008 - link

    My bad, you did indeed mention it.

    I'm curious what the problem was, be it user, MS, 3rd party, etc... I've not seen it and the only place I have heard about it was on the user forum linked in the article.
  • IAMGOOSE - Wednesday, February 27, 2008 - link

    "We’re still waiting on someone besides Apple to start shipping consumer machines (or motherboards) with UEFI support, so this will be an issue we’ll pick up another day."

    Current intel branded boards allow booting from UEFI

    You guys should try it out, in a mini review or something
  • kilkennycat - Wednesday, February 27, 2008 - link

    Heading asks the question....... Reply
  • mechBgon - Wednesday, February 27, 2008 - link

    ...but may I make a suggestion: Vista and WinXP aren't, like, video cards, where framerates are all that matter. I frankly feel that the security advances of Vista are getting important in today's security landscape, and a comparison of WinXP SP3 versus Vista SP-anything deserves to cover that. Not much point in having another 10 frames per second in WoW, after the bad guys dropped an undetected keylogger into your system and stole your WoW stuff to auction it off. ;) Drop me a PM if you want to pick my brain on the subject... Reply
  • yyrkoon - Wednesday, February 27, 2008 - link

    Cant say I agree with your security views. Any OS(with a few exceptions . . .ME comes to mind) is only as good as the user using it.

    Not only that, the 'bad guys' can not 'drop' a key logger onto your system, unless the 'bad guys' you're referring to are in fact yourself. Files do not auto-magically appear on a system by osmosis, they are downloaded by the user using said system whether the user is actually aware of this or not. Setting up a system correctly will fix a lot of this, while common sense computing habit will take care of the rest. This includes setting up proper user/group policies, permissions, etc, and MAYBE using web based email if you're having issues with you email client being exploited in unexplainable ways.

    Been running XP Pro here for the last 3 years or so, and I have to say that since SP2, it has been fairly secure(once again; when set up proeprly), and I would not expect Vista would be any more reliable. Now since I beta tested Vista early on through to RC2, I KNOW for a fact that compared to XP, there ARE performance issues.
  • SilthDraeth - Thursday, February 28, 2008 - link

    You may be a security professional, but I have no knowledge of you on the ATOT security forums. MechBgon however is very active and has a proven record of being extremely knowledgeable. Heck he spends most days trying dissecting this stuff to find out how to fix it.

    I think you are fighting a losing battle if you go up against him...instead try to learn.

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