Didn't find any over/under scan compensation settings in the driver and what was there was greyed out.
No slider bars in the CCC to adjust either.
BTW, it's the latest Catalyst 10.3 package I'm using.
I reset the drivers to default and solved my 1080i OTA stutter problem.
And here a weird one;
On the PC desktop, it's now FULL screen and the setting is 1920x1080 24Hz
When in the media centre, it goes to 1920x1080 60p and this is where the underscan occurs.
I would have expected the OS driver to pass through to the WMC operations.
I also stumbled across the pane that allows me to diddle with the interleave method from Bob to Weave to various Adaptive modes.
What is recommended for 1080i OTA source material?
Have NO problems with 480i SD via catv, so is it possible the ATI interlace bug only affects 1080i?
Before the reset, I was playing with ALL the interleave settings and nothing helped.
I was almost resigned to buying an ATI 5670 for the extra power, but may wait as it seems OK for now and 1080p BD has always been OK.
I'll have another look at the TV and AVR settings.
Maybe try direct to display to isolate any AVR interference, but all the other STB's device are run through it with a single HDMI output to the plasma with no issues.
There is a TSTV box, a HD FTA box and a PBO, all 100%