We have noticed a problem since we installed KB2754296, which is an update to Microsoft Security Essentials where our CPU usage continually peaks at 100% usage.
Investigation reveals that the high usage is caused by process NisSrv.exe which is the Microsoft Network Realtime Inspection Service.
We use QNAP network devices and there is a small program called QGet which is used to contact the QNAP Download manager. QGet runs on the PC and communicates with the QNAP process, and is used to provide the QNAP service with instruction as to what files to download. When the QGet process is running the NisSRV.exe usage goes through the roof,slowing down the PC to a point where its is virtually unusable.
The version of QGet does not seem to matter and we have tested versions 2.1.5.0702 and 3.0.5.1009 and the result is the same.
The version of MSE is 4.1.5220 and in our installed version there is no way in which the Network inspection service can be disabled.
The only conclusion we can draw is that the two programs are incompatible. We have disabled the QGet program, since it is not really used much anyway, but MSE should never cause the problem in the first place in our opinion.
Possibly we should consider an alternative security program over MSE!