I have been running a dual monitor system using an ATI card and a Samsung 204b and samsung 997df sucessfully for about a year. (Mandriva 2010-2 - 64 bit). I had an initial problem with setting the resolution that was solved on this forum. This week I replaced the 997df with a Hewlett-Packard HP LP2065. Windows accepted the change and is running dual boot. Linux is using both monitors ,but the screen goes black on the HP regularly (say 2-4x per minute). Sometimes it seems related to what is running, sometimes it does it with nothing running. The Samsung 204b is still running normally. I also have hooked the HP monitor up to a docking station on a laptop (running ubuntu linux and it works with no blacking out there (as a dual monitor with the laptop screen. I am certain the hardware is good but cannot stop the blacking out. The system did automatically recognize the HP monitor and wrote stuff in the xorg.conf to support it.

Any ideas, I am back to using the two samsung monitors....

John

Well, I solved it sort of.... The new monitor had a DVI plug, while the old monitor (997df) had a vga plug. The ATI card had a DVI plug with a splitter to two dvi plugs.. I put a DVI to VGA plug on the monitor, the vga cable and a vga to DVI adapter again at the card end. Now it works. I have no idea why it works, but it does.
John