The blog title is not entirely correct - MapGuide/AIMS is not directly affected, but - here are the details:
Suddenly (Monday morning) users started to complain that our AIMS based WebGIS is particularly slow. As it turned out it was not AIMS server itself but the application around it which was slow. Opening a form or performing a search suddenly took seconds, but map creation was still fast as usual. We do not use AIMS's Industry Model but TBVIEW1 as an better performing alternative.
We have three servers in use - the issue occurred only on one of them. TaskManager showed some unusual activity on the machine affected - it appeared as process MsMpEng.Exe was running nearly constantly consuming 25% of CPU power. Further investigation showed, that MsMpEng got active as soon as the WebGIS application interacted with Oracle, for instance when opening a form and remained active for some time. No other processes were using CPU power at the same time. For testing purpose our IT disabled MsMpEng.exe temporarily and the performance returned back to normal. They are now investigating why this happens and why it happens only on one of three machines (W2008R2).
AIMS 2013, SP2