CSS3 PIE: divs with border-radius flickering on mouseover

I'm using CSS3 PIE to add support for border-radius to IE6/7/8. It works perfectly, but I've found that when I use it to apply a "thick" border with rounded corners to a <div>, the border flickers when the mouse moves over it.

I did some testing and found that the flickering occurs only when the border width is 3px or higher, and regardless of any content in开发者_高级运维 the <div> (meaning, it can be completely empty and will still do it).

I searched the CSS3 PIE forums and didn't find an answer; the closest thing I could find sounded very similar, but had to do with using PIE on links rather than <div>s. The fix that was proposed - setting a background property on the element - doesn't work in my case.

I may have solved this myself (or at least negated it)...I had been testing IE8 and 7 by switching the rendering mode in IE9 (I don't have "real" copies of IE8/7 to test). Just for the heck of it, I tried the same page in IETester and there's no flickering at all.

So, since the issue has something to do with IE9 emulating IE8/7, I'll assume it doesn't occur in real installations (maybe HTCs don't execute at full speed under different rendering modes?).