Performance - Task manager for 1 - 2 minutes at 50%

Question

Hi,
I know that performance is discussed before...
Overall Lightroom is quick, but I have the following problem.
With several functions Lightroom goes to 50% of CPU capacity that stays the same for 1, 2 or more minutes. Looking at the taks manager, no byte is written or read. Absolute no I/O actions, only 50% CPU capacity. I have included the specs of my machine below.
Added: Only from time to time during this period the memory usage increases little.
At this moment it happend when I selected 10 smart collections and deleted them. But it also happens when I open a Smart collection with 10 images or even a normal collection with 3 images. I even had it once when I hit the F2 key to rename my images.
It is always the same behavior. CPU goes to 50%, stays like that for several minutes and then I can go on working and Lightroom is quick.
It always happens shortly after I start LR. Later on it happens from time to time.
On the otherside LR is quick, only from time to time it goes to 50%.
Lightroom version: 3.3 [711369]
Operating system: Microsoft Windows XP Professional Service Pack 3 (Build 2600)
Version: 5.1 [2600]
Application architecture: x86
System architecture: x86
Physical processor count: 2
Processor speed: 3,0 GHz
Built-in memory: 2047,0 MB
Real memory available to Lightroom: 716,8 MB
Real memory used by Lightroom: 116,9 MB (16,3%)
Virtual memory used by Lightroom: 109,5 MB
Memory cache size: 31,4 MB
System DPI setting: 96 DPI
Displays: 1) 1280x1024
Serial Number:
Application folder: C:\Program Files\Adobe\Adobe Photoshop Lightroom 3.3
Library Path: D:\Lightroom\FotoDatabase\FotoDatabase-3.lrcat
Settings Folder: C:\Documents and Settings\Dick\Application Data\Adobe\Lightroom

Answer 1

It could be syncing the changes you made to the DB, or adjusting extents (or whatever they are called in SQLite) because it detected there were enough changes to do so, and nothing much is going on. Most of the examples you give make a fair number of changes to the catalogue database.
Do you have an architecture that supports hyperthreading?  If so, there is  know issue where virtual threads can queue up in a less ideal manner when the stackframes of the physical threads are the same depth.
Then again, if nothing much else is going on, and Lr needs CPU for a lower priority thread, it will be given all the CPU it needs. That is, it is not necessarily a pathological case for an app to be given a fair chunk of CPU for some time frame, as long as it can be pre-empted in a reasonable manner.
Activity monitoring is only part of the story. You would really have to profile the app to know if this was a real problem. Put another way, is this causing resources not to be given to other apps or processes, or interfering with the higher priority threads (e.g., the UI or develop operations) in Lightroom?