0.75 High CPU usage and poor performance

[photoken]

OS Name: Microsoft Windows 7 Home Premium
Version: 6.1.7601 Service Pack 1 Build 7601
System Type: x64-based PC
Processor: Intel(R) Core(TM) i7 CPU Q 820 @ 1.73GHz, 1734 Mhz, 4 Core(s), 8 Logical Processor(s)
Installed Physical Memory: (RAM) 8.00 GB

I've noticed severe performance problems with 0.75:

• When using the mouse wheel to scroll through a directory of images in the Browser, there is a lag between initiating the scrolling and the actual scrolling of the view. This lag has been anywhere from a fraction of a second to a few seconds.
• When viewing images in full screen and using the spacebar to advance through the images, there is also the same lag of a second to a few seconds.
• Various other operations have caused XNviewMP 0.75 to become "unresponsive" for a while.

While viewing images in full screen and advancing through the images (and noticing some delays when using the spacebar to advance the images), I got a warning message from Norton System about High CPU usage for XNviewMP. When I opened the Windows Performance Monitor, sure enough, all 8 virtual CPUs were pegged at about 98%. This image directory has 25,000 images (all JPGs -- no RAW images, no TIF images, etc.). The directory is excluded from cataloging.

I uninstalled 0.75, rebooted, and installed 0.72. The same image browsing caused no delays, and the Performance Monitor showed 3 CPUs at about 50%, and 2 CPUs at about 30%, with the other 3 CPUs near zero. These tests were done with no other applications running.

[xnview]

I can't reproduce, are you able to reproduce it each time?