Exponential algorithm slows down Windows XP

    Windows Update developer Doug Neal explained why many Windows XP users have recently experienced performance issues after installing the latest updates.

    As the study of logs from "slowed down" machines showed, the problem lies in the inefficient method by which the Windows Update Agent module processes long lists of previous updates. List processing time increases exponentially with each new update. In other words, processing a new update takes twice as much time as the previous one.

    A huge number of patches have been released in the history of Windows XP, so when processing a list of 40+ old updates, the svchost.exe process starts consuming a lot of CPU resources, and this noticeably affects the overall system performance.

    The situation is mainly observed on Windows XP systems with IE6 or IE7 browser installed, but not with IE8 browser. Due to security requirements, Internet Explorer has the right to build the above chain longer than is normally allowed for Windows Update. Over time, this exception caused a problem due to a previously unknown bug in the Windows Update Agent.

    The Microsoft Security Response Center division gave permission to reduce the list of processed updates, and the Windows Update developers tried to fix the bug. In October of this year, they reduced the list on the backend side, but it didn’t help: “It turned out that the Windows Update Agent was pretty smart and outwitted us,” says Doug Neal, “so the problem remained for most affected users.” A more complete change to the backend was made in November, and one more in December. Unfortunately, the problem still could not be fixed.

    Unfortunately, service packs are released once a month, so the next attempt will fail until January. Doug Neal assures that this problem is now of the highest priority - and the right (and most intelligent) people were thrown at its solution. The official KB newsletter will be released soon with a more detailed description of the situation, but there is no official way around it. Unless permanently disable Windows Update.

    Forums joke that Microsoft has found the perfect way to get Windows XP users to upgrade to newer versions of the operating system. Official support for the longest-running OS in the Microsoft line ends in April 2014, and before that it is enough to release a dozen empty updates.

    UPD A commentfrom Aleksey Solomin ( IRainman ): “In Windows 7, you can clean up the tails for Windows Update through the“ Disk Cleanup ”tool, the“ Clean Windows Updates ”item, this feature was added only in Windows 7 and newer editions. Also, please note that if someone installed Windows 7 SP1 from scratch recently, then at the first updates it becomes very bad, while the auto-update service eats up the processor, and can consume several GB of memory. The problem really applies to all versions, just on Windows 7 and older is less noticeable. "

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