Running dual monitors at different refresh rates

[GoogalyMoogaly]

Hi,

I'm wondering if I need to do anything special when running 2 monitors at different refresh rates?

Basically I use 1 screen for gaming and the other screen for web browsing, temp monitoring, etc.
I've got 2 120Hz monitors, but due to AMD's wisdom the 7900 series cards only has 1 DVI port and both my monitors need DVI to run at 120Hz. I've tried using an active DP-to-dual-link DVI adaptor, but it doesn't work.
Now since the screen isn't doing anything much except displaying desktop stuff it doesn't really need to run at 120Hz, 60Hz would be fine.

However, when I set one monitor to 120Hz on a DVI cable and the other monitor to 60Hz using an HDMI cable, something odd happens. The 60Hz screen seems laggy and very jumpy and un-smooth. If I drag a window from the 120Hz screen to the 60Hz screen if starts stuttering. If I drag it back onto the 120Hz screen it remains stuttery until I 'drop' it and start dragging it again.
Also when playing BF4 it seems to cap the 120Hz screen at 60fps and ruins my framerate (which was running at around 90fps, but drops to about 50-60fps).

Am I doing something wrong? Can I run one 120Hz monitor at 120Hz and one 120Hz monitor at 60Hz?

If I run both at 60Hz it seems to eliminate the issue, but since I have 120Hz screens I like to run the one I game on at 120Hz if possible.

Any ideas?

Thanks.

EDIT: Just thought that this should probably have gone in the 'Monitors' sub-forum...

 

[LtMatt]

Drop Thracks a trust message and ask him, assuming no one knows the answer here.

 

[Sin_Chase]

Some Googling reveals that disabling Aero might resolve the issue?

On that topic, what OS are you running?

Using DVI and DVI on a 680 drives 120Hz and 60hz fine so it might be an issue with using DP/HDMI...which as you pointed out..is your only option.

 

[Addicted]

There are some hacks to force the driver to output at 120hz, you need Custom Resolution Utility and the hack, if you google around you'll find it, presume I can't link it here.

 

[GoogalyMoogaly]

I got around the better way, but a way that required more effort on my part.

I knew in advance that the Active DP-to-Dual-Link DVI adaptor doesn't always seem to work when powered by the motherboard, so I had a powered USB hub ready and waiting.
I just found that and set it up, then plugged the adaptor into that.
So the screen now works at 120Hz via DP/DVI.

Probably the better solution really, but still don't think I needed 120Hz.
Sorta knocks my idea of a 1440p/1600p 60Hz monitor and 120Hz 1080p monitor combo idea on the head though.

Thanks for the help guys. I'll have a look for the hack, just out of interest (and in case I got 1440p/1600p).