dual monitor setup with amd 7950

[javier_machuk]

My gigabyte 7950 just arrived today, installed, and everything seems fine, the problem is that when i use two monitors for extended desktop the GPU clocks go to 500 MHz and the memory to 1250MHz, i searched about it in google and it seems like a common problem, my question is:

Can i plug one monitor to the integrated graphics of my mobo(asus z68-v and i5 2500k) and the other one to my 7950? if that is possible, would it allow the 7950 to use full iddle clocks? BTW i'm using win7

 

[KingFatty]

Yes, connecting one display to the 7950 and one display to a separate video card should work to let the clock/memory speeds go low again.

Also, you can use the windows key + P to toggle between the extended mode where both displays are active, to singe-display mode where the second display is disabled. That should also allow the core/mem speeds to go low.

If you want to get advanced/tricky, you can connect both displays to the 7950, and then also have a 3rd cable going from one display to the second monitor. Then, you can mix/match by changing the input etc. Probably more complicated work than necessary, but hey maybe that would serve your purposes too (not sure if you want to toggle between dual-monitor on the 7950 to dual montor on both video cards to allow the 7950 to go to low speed)???

 

[javier_machuk]

Yes, connecting one display to the 7950 and one display to a separate video card should work to let the clock/memory speeds go low again.

Also, you can use the windows key + P to toggle between the extended mode where both displays are active, to singe-display mode where the second display is disabled. That should also allow the core/mem speeds to go low.

If you want to get advanced/tricky, you can connect both displays to the 7950, and then also have a 3rd cable going from one display to the second monitor. Then, you can mix/match by changing the input etc. Probably more complicated work than necessary, but hey maybe that would serve your purposes too (not sure if you want to toggle between dual-monitor on the 7950 to dual montor on both video cards to allow the 7950 to go to low speed)???

thanks for the help! should i reinstall the intel HD drivers again then? because i uninstalled it before i put the new GPU in. Currently i only have catalyst video driver on my PC

 

[KingFatty]

I'm not aware of any conflicts between the intel drivers and the AMD drivers. I say go for it, but be wary in case any conflicts develop. However, anecdotally I think most conflicts are when people mix Nvidia and AMD, just that I haven't heard of conflicts between Intel and anyone else? Always do a backup first.

 

[Dstoop]

I'm not aware of any conflicts between the intel drivers and the AMD drivers. I say go for it, but be wary in case any conflicts develop. However, anecdotally I think most conflicts are when people mix Nvidia and AMD, just that I haven't heard of conflicts between Intel and anyone else? Always do a backup first.

I've never had an issue leaving integrated drivers installed side by side with drivers from a discrete card. We used that exact setup for dual monitors on all PCs at my last job (which was at a very large company with over two dozen major offices globally), and I don't think I ever saw a single ticket cross my teams queue that was traced to a conflict between the two drivers. That's not to say it's completely impossible, but I think it's safe to say that it's unlikely. One monitor on each video device is a totally viable solution.

 

[Lonyo]

I use my HD7950 and Intel HD4000 (IB on Z77 or something) without any issues, specifically for the downclocking reasons. Not had any real issues to date, although Intel does seem to be funny about my turning off my monitor, and thinks it's disconnected fully, while the AMD card is fine with me turning off the screen.

 

[javier_machuk]

thanks for all the inputs guys! i will reinstall the intel drivers and try out with one monitor each, i'll update on how it goes!

 

[javier_machuk]

ok.. i had to activate the iGPU in the bios, then i just plugged one monitor to the hdmi port on the mobo and restarted the computer. Windows detected the iGPU automatically and said that the device is ready for use, it is working fine now, the 7950 is iddling correctly and i have set the extended desktop mode to the other monitor.

Just one final issue, since my wallpaper is an all black solid color, when i had both monitors connected to the same GPU and didn't had anything open on the second monitor the backlight turned off completely and when i opened some window in that screen only then the backlight turned on. Now the second screen backlight is ON even when nothing is in it(just black solid color), do you think that could be an issue with how windows automatically installed the driver? should i install the Asus supplied HD graphics driver anyway?

 

[KingFatty]

That might be an HDMI issue, maybe your HDMI cable doesn't support the signal or something from the Intel output? Any way to connect that monitor via DVI to the intel, then use the HDMI cable on the 7950? Or just mix/match the cables/connections to see if you get the results you want. maybe check the power profile info in the intel driver settings?

 

[javier_machuk]

just realized that i have another problem!:| when my computer is at long idle(and the monitors turn off) one of the cores of the cpu goes to ~80% load, i realized about it by leaving the task manager open and letting the computer go idle. When i press any button and the screen turn back on i can see in the task manager how much CPU was in use. Unfortunately i don't know how to look which process was using the cpu because when the screen turn on, the cpu activity instantly go to ~0% as it should have been.

Anyway if i disconnect the display that was on the iGPU the above case doesn't happen and everything is normal.

So as it stand now i have two options

1. connecting 2 monitors to the discrete gpu and letting it idle at 500 MHz core and 1250 MHz memory.:\

2. connecting one monitor to the iGPU and one to the discrete GPU and making my CPU load at idle go nuts.

anyone have an idea of what might be causing the high CPU load with the screens off?

 

[KingFatty]

There is a 3rd option:
Connect both monitors to the discrete GPU, but use Win+P hotkey to disable the secondary monitor when you don't need it to allow the video card to idle at lower/single-monitor speed and save more power. I use this setup on my triple-screen setup, where I use Win+p to disable my side monitors and just use the single middle display when I'm browsing/gaming and not using the side monitors. My card is therefore almost always idling at the lowest speed because only one display is active, so that doesn't trigger the increased core/mem speeds you are seeing even though the displays are still physically connected.

There is also 4th option:
Modify a copy of your card's bios to use lower core/memory speeds for when multiple monitors are connected. You might get some odd glitches here and there, but it could work, though I much prefer the 3rd option above.