What version of VSE are you running?
8,7i with patch 2.
Unless you are low on resources you should not really experience this issue. Will investigate any options.
At this time there aren't any known issues outside of a small memory leak within the 5300 Engine and 5400 Engine resolves this issue. When I've has to troubleshoot issues with high CPU during an update I have to use Process Monitor to identify what is the root cause of the issue. This normally results in an exclusion or Low-Risk process.
What you describe may be the same behavior discussed in this thread:
VirusScan now tries to use a more optimal method of managing memory, and for the most part it successfully utilizes it - this is done by creating a "Runtime DAT" when the scanners initialize. However, if we fail to create that DAT, the product reverts to the prior method of managing memory which is more costly to the system's resources.
This memory management improvement was introduced with Patch 1 for 8.7i.
Unfortunately, there is no other method to reduce memory usage. But user-impact can often be reduced with a variety of options alluded to by my colleagues, it just takes a little investigation to see what's appropriate. If we learn the impact is due to the scanners using the fallback memory management method, please let us know - there may not be a solution to improve that in the short term but knowing the root of an issue is half the battle.
Also if you refer to the other posting, you'll see there is a registry tweak that can be made without doing any diagnosis first.
You may also want to look at the "Scan processes on enable" option in the OAS policy. Updates do trigger this scanning--even if they came from a SuperDAT.