Capture NX2 glitch

Hello group,

Wonder if anyone can help me with this: I have Capture NX2 v. 2.3.1, the latest. When I move sliders in unsharp mask, the image responds, but then, after a few seconds, the sharpness, as defined by intensity and radius, drops back a bit, becoming a little less "sharp." But the sliders do not move back, however. So I have to move the sliders beyond where I really want them to get the right effect. This "dropping back" is reflected in the histogram. All this means more fiddling around than I want.

Hardware info: Nikon D90, 18-200 VRII zoom, 5-year-old HP Pavilion a1700n computer with 150 GB free hard drive space, 3GB RAM, AMD dual-core processor. Latest graphics driver update.

I'm wondering if the fault lies with the software or the computer. Thanks in advance.

Ron