Topic Title: Dual Graphics doesn't work
Topic Summary: Dual Graphics doesn't work, though it seems activated
Created On: 08/27/2014 04:33 AM
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 08/27/2014 04:33 AM
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DarthLuda
Peon

Posts: 3
Joined: 08/27/2014

Hello everybody,

I recently upgraded my APU from A10-6700 to A8-7600.

The reason is that the Dual Graphics configuration (8670D + R7 250) did not work (though CCC said it would).

Now, I am experiencing the exact problem as before. Benchmark results didn't change at all (Only about 200 in Unigine Heaven 4.0, Extreme Preset / about 1000 points in FireStrike), no matter whether Dual Graphics is enabled or not.

In UEFI, I set Primary Graphics to PEG instead of IGD and Dual Graphics to ON, Allocated RAM to 2GB. iGPU Clock is set to 1016Mhz in UEFI.

You find my system specs below.

I am using the latest beta driver (Aug-14).

Any ideas?



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MB: MSI A88XI AC // APU: A8-7600 // GPU: XFX R7 250 2 GB DDR3 // RAM: Mushkin 8 GB DDR3-2133 Single Channel // OS: Windows 7 64

 08/27/2014 08:20 AM
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black_zion
80 Column Mind

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Joined: 04/17/2008

Yea, buy a 260x and have more performance than any dual graphics setup without any of the drawbacks.

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ASUS Sabertooth 990FX/Gen3 R2, FX-8350 w/ Corsair H60, 8 GiB G.SKILL RipjawsX DDR3-2133, XFX HD 7970 Ghz, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, HP ZR2440w, Win 7 Ultimate x64
 08/27/2014 10:43 AM
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DarthLuda
Peon

Posts: 3
Joined: 08/27/2014

Originally posted by: black_zion Yea, buy a 260x and have more performance than any dual graphics setup without any of the drawbacks.

Sorry, but this is not very helpful.

A 260x consumes about 40 Watts more and is not available as a Low Profile card, what is not really practicable for my Mini-ITX-System.

Also, I set up my hardware like this because others already had better results with this combination.

Anyway, I chose the APU driver on the AMD website. Is there any difference between chosing this or the R7 driver?



-------------------------

MB: MSI A88XI AC // APU: A8-7600 // GPU: XFX R7 250 2 GB DDR3 // RAM: Mushkin 8 GB DDR3-2133 Single Channel // OS: Windows 7 64



Edited: 08/27/2014 at 11:11 AM by DarthLuda
 08/28/2014 02:15 PM
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DarthLuda
Peon

Posts: 3
Joined: 08/27/2014

I figured it out.

You NEED RAM with at least 2133 Mhz and (more important) two identical bars running in dual channel mode. It's because this increases the iGPU bandwidth from 17GB/s to 34GB/s, so it is comparable to the GPU bandwidth (28 GB/s in my case).

All my benchmark scores increased by 50 to 100%.

Hope this helps everyone who experiences similar problems.

 

UPDATE: I also figured out that you have to change the clock speed of both the iGPU and the GPU as well to minimize asynchronic rendering.

iGPU: 720 to 800 Mhz // GPU: 1050 to 900 Mhz

Hope this helps



-------------------------

MB: MSI A88XI AC // APU: A8-7600 // GPU: XFX R7 250 2 GB DDR3 // RAM: Mushkin 8 GB DDR3-2133 Single Channel // OS: Windows 7 64



Edited: 08/29/2014 at 05:55 PM by DarthLuda
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