Workflows upsetting IIS - suspended status

Folks,

I've got an issue with one on my geoapplication servers that hosts GXE. When I run a workflow (it is not a specific one), IIS seems to want to suspend itself - whatever that means. I can't find a lot of reference material on the web as to what this issue is. I'm on win2012/IIS8.0

Sometimes the workflow performs well, the next time you run it - IIS work process suspends itself, and it hangs for a while! It doesn't crash - it just sits there for 10-20 seconds or so..

any thoughts welcome. I have another geoapplication server in the Load balancer that is behaving itself nicely, but this other one on it's own is a nuisance! They are built from the same VM clone and I cannot see any differences in why they should act any differently!

/customer/servlet/servlet.FileDownload?file=00P6000000em1ZuEAI

any help appreciated

cheers 

Gareth