I just did the March update. I have re-enabled the offending tasks and I am going to try and see if this update fixes my high CPU usage issues. I did not have this SP2 long before I applied the Feb update, but I did not notice problem until after the update. Of course, my original SP2 (sans Feb update) seemed to exhibit a similar issue, so who knows. I am also interested in seeing if this update fixes my
wacky battery problems. Even if the issues appear fixed with this update, I can't help but feel that there are underlying hardware issue that these firmware updates try and work around. After all, the updates often affect users differently indicating that the hardware is not as "uniform" as it should be.
grumpy - If you go to MemoryDiagnostic you'll notice that it is not a scheduled task, it is a triggered task. Click on the "Triggers" tab for a list of things that trigger it. On my SP2 GDR1 machine all triggers are specific log/event IDs. Perhaps you can dig into the source of those events to find your problem
There are two memory diagnostic tasks - "ProcessMemoryDiagnosticEvents" and "RunFullMemoryDiagnostic". ProcessMemoryDiagnosticEvents has multiple defined triggers and initially I only disabled that task, but it did not alleviate the problem. It was was only after I disabled the RunFullMemoryDiagnostic task that the high CPU usage issues appeared to cease. I perused the logs and could find no clues to this behavior.
It has only been a short time since I re-enabled the tasks, but they have both since run and there have been no ill effects (yet) - so fingers crossed...