It isn’t a new bug, but it’s a killer, and this month’s round of Automatic Updates has brought it back with a vengeance. Freshly installed Windows XP SP3 machines running Windows Update — typically because Automatic Update is turned on — will stall twice. First, when Windows Update accesses the Microsoft website to gather a list of available updates, the machine can lock up for five, 10, 15 minutes — or more — with the CPU and fan running at 100 percent. Then, if the customer waits long enough for the updates to appear, and clicks to install them, the XP machine goes racing away again for five or 10 or more minutes, with the CPU redlined at 100 percent.

If you’ve turned on Windows Automatic Update, your brand-new WinXP SP3 installation may just sit there and churn and churn.

Microsoft has known about the problem for months — probably years — but it hasn’t fixed it. I first saw the problem described in a TechNet post for the June 2013 Black Tuesday patches. In September, reader warwagon on the Neowin support forum described the same problem — and drew more than 100 comments, many of which repeated the same story. Jeff Duntemann talked about the problem in October — and he traces its origins back to 2004.

Now the November 2013 Black Tuesday patches are bringing back the same litany, and Microsoft hasn’t made any moves to fix it.

Read the full article at: Windows XP update locks machines with SVCHOST redlined at 100%: Fix it with KB 2879017 | Microsoft windows – InfoWorld.

If you are suffering from this annoying problem the first thing to do is install KB 2879017.  I know it sounds stupid but you need to manually install that update ( which is an Internet Explorer update) to solve the slow down in Windows itself

The best solution appears to be a manual update to Internet Explorer. Yes, Microsoft has messed up wuauclt.exe so badly that it has to be repaired by installing an IE update — not a Windows update — to get it working properly. The fix is part of the October cumulative IE patch known as MS13-080/ KB 2879017. If you manually download and install the October cumulative patch, then you should be able to use Windows Update with no problems.
Operative term: “should.”

The precise download location varies depending on which version of IE you’re using. For IE6 go here. IE7 is here. And IE8 is here.

You would think that simply upgrading to the latest version of IE would solve the problem, but it doesn’t. You have to manually download and apply the patch for your version of IE.