Minimum and recommended hardware specifications are documented here.  It's hard to talk about "normal" CPU usage because the Laserfiche server doesn't do much by itself, most activity is in order to handle requests from users.  The more active users you have, the more hardware resources the Laserfiche server will require.  Lfs.exe regularly taking 40% of the CPU is not a problem in and of itself, but the thinking is that server demand is not flat, so there are probably times when the lfs process needs about double that.  The screenshot suggests that the machine would not be able to allocate sufficient resources to lfs.exe in that case.  My suggestion would be to either try to reduce the resource utilization of non-Laserfiche processes on that machine (i.e. MsMpEng.exe and whatever accounts for the 20% not visible in the screenshot), or to allocate more resources to this machine.