Strange cross fire problem

Setup…

A64 3700+ Diego
Asus a8rmvp x-fire ready Motherboard
1x Sapphire X1900XT 512MB Master
1x Sapphire X1900XTS 512MB Slave
2GB dual Channel Geil ram pc3200
Acer AL1951 19” Monitor
PSU is a Jeantech 700W

Original parts are below. He purchased the new motherboard because he thought the motherboard was at fault. He also replaced the PSU because he thought it was a power issue.

MSI rd480 neo2 x-fire ready
Antec 550w

The Problem…

My friend’s crossfire setup seems to be causing him a headache as crossfire does not seem to work over DVI. What happens is the screen flickers between the game and a blank screen, then when you quit the game it comes up “input not supported”

HOWEVER crossfire works on both my old monitors! A 17” Iiyama 431S prolite and my good old 17” Hitachi.

SO…

He went to PC world and purchased the Samsung 20” screen that’s on offer…

And guess what….

It does exactly the same as his Acer monitor “it flickers between the game and a blank screen”

This is a very strange problem, we have also swapped out the slave card with a friend’s and it does exactly the same thing (no other master card to try) BUT surely the master card can’t be to blame as it works on both my old monitors.

Any ideas??!?

:undecided

Does he have a refreshrate override in Windows or in DXDiag that tries to push the monitor over 60Hz?

input not supported generally means the graphics card is outputting an image that the monitor doesn't support. Any more than that, i don't know...

Not much use i know, but hey :D

Yeah CRT's can handle a wider range of resolutions and refresh than TFT's. So try plugging in the CRT, setting it to the correct res and and refresh rate for the TFT(It'll be in the manual), then swapping back.