[Garvio]

My dad has an old Powermac with a single monitor. However, the display preferences thinks he has two monitors. Hitting the detect display buttons detects two monitors. The system profiler says he has two monitors. This seems to cause some problems and sluggishness. Anyone know how to correct this?

Thanks

[reader50]

The system is probably splitting the graphics memory between the "two" monitors, hence the slowdown. Which PowerMac is it, and what graphics card(s) does it have? Better list any other cards installed too, in case one qualifies somehow.

If a display adapter is plugged into an extra display port, it will be read as a monitor even if one isn't connected. What does the system profiler say about each monitor? In particular, what info does it give for the phantom monitor?