svchost suddenly gobbling up huge amounts of memory

Factual Questions
1

Windows 7 Home Premium, SP 1

A couple of weeks ago svchost started consuming a lot of memory after the system had been running a while. Right now, for example, it’s using over 8G out of 16G of physical memory. All is good after a reboot but it gradually ramps up again.

Could a Windows update have caused this? Anything else I ought to know?

2

There will be several svchost instances, which are the host processes for various services. First thing you should do is right click on the instance which is taking all the memory and select “go to services”. This will bring up the services tab with the services that instance corresponds to highlighted.

3

Have you done a malware check?

4

It’s likely SuperFetch, this articles says “relax”
http://www.osnews.com/story/21471/SuperFetch_How_it_Works_Myths

You can switch it off though.
http://www.addictivetips.com/windows-tips/disable-windows-7-superfetch/

5

Grab yourself Process Explorer and dive down the rabbit-hole.

6

This was the first thing I did but Task Manager does not show memory consumption for the services.

Yes, comes up clean.

Funny, I have had this for a long time and forgot about it. When I saw your suggestion I refreshed to the latest version. This will be a very good tool for this situation.

Thanks to all for responses.

7

(this is basically Cugel’s commentary about superfetch explained a bit more)

One thing to keep in mind is that Win 7 has a different memory use philosophy than previous versions. Rather than try and keep the maximum amount of memory unallocated (and therefore unused), Win 7 tries to use RAM as much as possible, under the theory that unused memory is memory that could be used to speed something up. Superfetch will actually pre-load stuff into RAM that’s commonly used, even if it’s not needed at the present time.

So it’s not necessarily indicative of a problem if Windows 7 allocates most of its memory.

8

Agree with the principle, but what alerted me to it in the first place was that performance was suddenly in the shitter. Nearly every app was unresponsive or unusably slow. I think there was not enough free memory left for apps I was actually using to allocate enough.