AMD Dual Graphics with Mid Range GPU

[Zeals]

AMD Dual Graphics is a feature that allows the user to utilize both a dedicated graphics card along with their integrated GPU in order to gain higher frame rates. However AMD notes that the user shouldn't "unbalance" the two GPUs with the dedicated graphics card should be roughly on par with the performance on the iGPU, for the AMD A8-5600K they suggest the use of a HD6670 which is an entry level card. Despite this I wondered whether or not using a higher end graphics card would gain any performance when running a dual graphics set up or whether or not it is better to disable and ignore this feature. 

 

Test Setup:

 

AMD A8-5600K @ 4.2 GHz

2x4 GB G.Skill Ripjaw X @ 1866 CL9

XFX HD7870 GPU: 1100 MHz  Memory 1250 MHz

MSI A75MA-E35

iGPU HD7560D @ 844 MHz

We will be running a series of games and popular benchmarks. The games include ones that are developed with the help of either Nvidia and AMD as well as other popular game titles. All games will be run at max settings using the latest 13.11 Beta Drivers (22/11). The iGPU will be sharing 768 Mb of the 2 GB of GDDR5 Memory on the HD7870, this is the amount of memory that is allocated by default. 

Results:

The first benchmark we'll be looking at will be 3D Mark Vantage Run on Performance Preset:

Note: the way Excel scales the graph is misleading, when we run dual graphics we only see a slight 70 more Vantage points.

 

Now the rest of the benchmark results. As mentioned before all the following games and benches will be run at max settings at 1920x1080 using the latest Catalyst Beta Drivers.

Looking at the results for the synthetic Unigine benchmarks there is virtually no difference between the two. When it comes to games the performance difference is also negligible, with only a slight performance gain on some titles, while others stay the same and some titles such as Assassin's Creed 4 and LoL actually run marginally worse. Overall when you take into account fluctuations there is no difference in performance when you're running dual graphics or a single upper mid range card. 

 

Conclusion:

Looking at these results AMD Dual Graphics with an upper mid range card yields no benefits, and when I was doing the benchmarks I did notice minute amounts of screen tearing occurring when I was running dual graphics. When you take into account the negligible difference in performance for the best gaming experience there is no point in enabling dual graphics if you have a decent GPU, however other sites have shown that the slightly lower end HD7770 will see a slight 5-10% performance gain, however when running a dual graphics set up there is more screen tearing which can lead to an even worse gaming experience which I also suffered when running dual graphics. In conclusion the current generation of dual graphics should only be used with a low end graphics card, however in the future with the introduction of Kaveri which will have an iGPU the equivalent to a HD7770 upper mid range cards might gain a noticeable improvement. 

 

TL:DR JUST DON'T! Wait for next generation APUs before going Dual Graphics with anything higher than a HD7750.

[eX.Drunk]

lol even an HD 7770 can give you constant 120 fps on ultra at dota 2. Your 7870 chart must be wrong

[Zeals]

lol even an HD 7770 can give you constant 120 fps on ultra at dota 2. Your 7870 chart must be wrong

Those are the frame rates FRAPS is telling me. Having said that DotA 2, like most other Source Engine games tends to be a bit more CPU bound than GPU bound, using an APU could be the reason for that

[Torand]

lol even an HD 7770 can give you constant 120 fps on ultra at dota 2. Your 7870 chart must be wrong

 

He never stated what resolution he was running the games at.

 

What resolution ARE you running the games at @Zeals ?

 

You really should put that info in, otherwise bench marking makes no difference...

[eX.Drunk]

Those are the frame rates FRAPS is telling me. Having said that DotA 2, like most other Source Engine games tends to be a bit more CPU bound than GPU bound, using an APU could be the reason for that

Yes that could be the reason but dota 2's minimum requirements consist of a p4 with 3.2ghz clock speed. Surely AMD's A8-5600K @ 4.2 GHz surpass the recommended requirement of the game. 

 

 

He never stated what resolution he was running the games at.

 

What resolution ARE you running the games at @Zeals ?

 

You really should put that info in, otherwise bench marking makes no difference...

Even at 1440p you won't see much of a difference though. i have played this game with a 7850 with ultra graphics on 1080p at constant 120 fps and during aggressive battles 80 at most.

Right now i run it with GTX 570 OC version which is almost as fast as a 7870. since nvidea has physx and stuff it can make a difference but what about the 7850. it gave me higher fps on ultra than 7870 at default clock speed which is not possible =O

[Apach3]

the same is true for laptops. i have a laptop with an A10-4600M APU and an HD7730M GPU, and with Dual Graphics on i don't see much of a difference. that's why i keep some applications on the integrated GPU and others on the discrete GPU.

[Zeals]

He never stated what resolution he was running the games at.

 

What resolution ARE you running the games at @Zeals ?

 

You really should put that info in, otherwise bench marking makes no difference...

All benches are done at 1080p except for Vantage which is done on the Performance Preset which I believe is 720p can't believe I overlooked that detail >.<

[Zeals]

Yes that could be the reason but dota 2's minimum requirements consist of a p4 with 3.2ghz clock speed. Surely AMD's A8-5600K @ 4.2 GHz surpass the recommended requirement of the game. 

 

AMD CPUs do occasionally have an odd way of interacting with games. World of Warcraft for example is basically capped at 80 FPS unless you get an Intel CPU. Probably something to do with the way the architecture that handles a particular instruction set that is particularly prevalent in the World of Warcraft and Source Engines, but for most games the A8 is fine and doesn't create any real bottleneck issues and when it does the frame rates are more than playable, especially for someone that only has a 60 Hz monitor