I have just tried connecting my iMac to two plasmas with HDMI. One tv is 1080p, the other 1080i. I have set up a splitter to send the signal to both TVs. They both receive the signal fine at 1080i. However, when I turn the TVs off, the iMac continuously refreshes the whole screen, as if it is trying to change resolutions. So it works fine while the TVs are on, but starts doing this refresh thing when they are turned off.. Any ideas why this is happening?