my i3 530 works fine with a HDMI monitor in power save mode. It does not us CEC to do this, just goes to sleep and the monitor shuts off but it's partly up to the monitor and all the incapatibilities of the POS HDMI interface. I have an ASUS monitor that does not go to sleep in HDMI mode never. so it might be your monitor.
I have another problem with the i3 in that 2 HDMI monitors I have must be power cycled every time the i3 machine goes to sleep, they montors work fine with sleep mode with other video cards so it seems to be an i3 issue, or another POS HDMI interface problem.