AMD Hybrid Crossfire Review [Tom's Hardware]

[Enigmoid]

Well it looks like hybrid graphics is pretty much a gimmick. AMD's hybrid crossfire system suffers from the same problem as the 7990 (before the new drivers). Very high values reported from FRAPS but poor gameplay.

We can discern that fraps wise, dual graphics with a 6670 GDDR3 imcreases performance 48% over what the GPU alone would give. With a GDDR5 version, fraps fps increases 30%. There is no point to hybrid crossfire with a 7750.

However, the gameplay between hybrid graphics and simply the igp is exactly the same due to the tremendous stuttering hybrid crossfire introduces.

For example

Tomb Raider

Looks pretty good

then...

And the video tells the whole story

http://www.youtube.com/watch?v=kb-HOrr4Bb8&feature=player_embedded

Skyrim appears to show lower variance with dual graphics but the video feed is laggy as hell and pretty much the same as the a10-6800k alone.

http://www.youtube.com/watch?v=ZtcCIF1MgsE&feature=player_embedded

Conclusion

With that said, the latest driver doesn't help Dual Graphics. And the problems with this technology are more severe than we imagined even before this story was conceptualized. We're hoping the company gets serious about fixing Dual Graphics, just as it did when it committed to improving CrossFire with two discrete GPUs. Right now it's evangelizing a feature that helps improve benchmark results, but not actual gameplay. That's just not right.

At this time amd needs to get their **** together. There is exactly 0 point to dual graphics.

 

[Red Hawk]

Isn't Richland still using VLIW4 architecture for the GPU component? The Radeon HD 6670 uses the older VLIW5 architecture, while the 7750 uses the modern GCN architecture. Due to this, the CPU graphics and both discrete graphics cards process data in fundamentally different ways. I'd imagine this introduces significant compatibility problems to begin with -- last I knew, hybrid graphics didn't work with GCN based cards at all -- before you even get to leveling out frametimes. It may just be that this is a fundamental hardware problem that drivers can't fix. It would be nice if AMD could look into a framepacing solution like that are working on with Crossfire, but the same thing may simply not work. I'd be interested if anything changes when Kaveri comes along with GCN graphics on the processor, or if things were any better back with Llano when the processor graphics and discrete graphics were both VLIW5.

Right now, you're right, hybrid graphics is pretty terrible. Graphics enthusiast gamers on a budget should just forgo trying to get a hybrid graphics setup and get an Intel Haswell CPU or a graphics-free, more cores/higher clocked AMD Vishera CPU the way things are.

 

[Silverforce11]

Im amazed they even got it to work with entirely different architectures.

But its not a serious solution anyway so not even sure why they are bothering with it. Waste of man power.

 

[ViRGE]

Isn't Richland still using VLIW4 architecture for the GPU component? The Radeon HD 6670 uses the older VLIW5 architecture, while the 7750 uses the modern GCN architecture. Due to this, the CPU graphics and both discrete graphics cards process data in fundamentally different ways.

I wouldn't call VLIW4 and VLIW5 fundamentally different (VLIW4 really just exchanges fewer lanes for more SIMDs), but they're just different enough that it can cause a problem. Trying to pair up GPUs that don't have identical instruction latency is always a dicey proposition.

 

[exar333]

AMD should be ashamed of this (as should anyone). They are essentially marketing to the user to pair their APU with an affordable GPU (like the 7750) and then the user actually gets WORSE performance than if they just used the 7750.

This is absolutely terrible.

 

[bystander36]

Im amazed they even got it to work with entirely different architectures.

But its not a serious solution anyway so not even sure why they are bothering with it. Waste of man power.

Sadly, I see a lot of people coming to the forums asking about it, and why they still have poor performance.

There is a market, even if it product currently sucks.

 

[Stuka87]

This needs to be retested when APU's that utilize GCN are released. Obviously there will be issues between VLIW4/5 and GCP cards.

 

[bystander36]

This needs to be retested when APU's that utilize GCN are released. Obviously there will be issues between VLIW4/5 and GCP cards.

As the author of the article pointed out, it also does not work with the frame pacing driver. AMD specifically told them it wouldn't work with the new drivers. I'd think once the drivers are designed to have frame pacing, it might start to work well or at least reasonable.

 

[KingFatty]

Sometimes you wonder, is AMD hurting itself by offering this hybrid feature that works but is not perfect?

Would it be better to take a different approach, and refuse to offer the feature altogether and just say it doesn't work?

Many people are troubled by getting an extra feature, if that extra feature is not perfect. I think AMD should just disable hybrid altogether, then people couldn't complain about it as being non-perfect. Give someone a horse, and he will complain about it's teeth.

 

[exar333]

Sometimes you wonder, is AMD hurting itself by offering this hybrid feature that works but is not perfect?

Would it be better to take a different approach, and refuse to offer the feature altogether and just say it doesn't work?

Many people are troubled by getting an extra feature, if that extra feature is not perfect. I think AMD should just disable hybrid altogether, then people couldn't complain about it as being non-perfect. Give someone a horse, and he will complain about it's teeth.

It's not 'not perfect', it's a worse solution than just using the discrete card in many cases. They should not market this and just disable until they have an acceptable fix. Sure, it doesn't need to be appreciably faster in all cases (or even many cases) but it shouldn't be noticeably worse in almost all applications. That's terrible customer service IMHO.

 

[zlejedi]

It's been like this since day one. The sad thing is some notebooks are sold with hybrid.

 

[frozentundra123456]

It's been like this since day one. The sad thing is some notebooks are sold with hybrid.

Well, to be blunt, it sounds good from a marketing standpoint and in fanboy posts on tech forums, and like most other companies, they probably don't really care about the customer experience once the sale is made.

 

[JAG87]

404 - vsync not found

 

[Red Hawk]

Apparently things aren't all bad, though. Take a look:

Dual graphics manage lower frametime variance in Skyrim across the board, though reportedly 6670 dual graphics gameplay still feels just as choppy as the 6800K by itself. They don't say what 7750 dual graphics gameplay feels like.

The 7750 dual graphics doesn't have nearly as much of a frametime jump as the 6670 dual graphics does. Again though, they don't report on how 7750 dual graphics subjectively feels.

Again, 7750 dual graphics has much lower frametimes than the 6670, though it has no real advantage over simply using a 7750 alone. THW left out any subjective comparisons because gameplay was unacceptable on any solution, really.

Similar situation with Bioshock Infinite.

My conclusion is that Dual Graphics may not actually be so problematic on 7750 setups...but there also seems to be no benefit to using 7750 dual graphics over a solitary 7750. That's just as undesirable in the other direction, really. But the fact that it works with lower frametimes gives me hope that AMD just may be able to fix it with something like a framepacing solution.

And before you ask "Where's FCAT?", apparently FCAT did not work with the AMD dual graphics setups.

 

[Haserath]

Sometimes you wonder, is AMD hurting itself by offering this hybrid feature that works but is not perfect?

Would it be better to take a different approach, and refuse to offer the feature altogether and just say it doesn't work?

Many people are troubled by getting an extra feature, if that extra feature is not perfect. I think AMD should just disable hybrid altogether, then people couldn't complain about it as being non-perfect. Give someone a horse, and he will complain about it's teeth.

They sell you an extra horse that makes you expect it to pull the buggy faster, but it doesn't.. If they offer a feature, it should work as advertised, otherwise it might as well not be there at all.

I can only compare it to apple maps leading people through walls. It becomes pointless if it's bad.

 

[KingFatty]

More like AMD is offering a horse that is really two midgets wearing a horse costume, and one of the midgets has a peg leg.

 

[Madpacket]

Anyone know if AMD will be bringing frame pacing to these hybrid setups?

 

[BrightCandle]

Anyone know if AMD will be bringing frame pacing to these hybrid setups?

We are all surprised that frame pacing wasn't universal to begin with. I suspect this is the reason toms did this test now, to check if the frame pacing release did target this or not. Clearly it doesn't.

 

[f1sherman]

More like AMD is offering a horse that is really two midgets wearing a horse costume, and one of the midgets has a peg leg.

And the other midget is special olympics champ?

 

[ShintaiDK]

Hybrid CF never worked. The concept when you think of it is also terrible. And will always be bad.

CF and SLI is GPUs taking turn to render a frame. And any inequalities instantly creates a case where you either lose massive performance or completely break any chance of somewhat synced frames.

AMD should instead simply have offered it as a way to put the dGPU into sleep when not gaming. And then add a more or less complete poweroff of the GPU setting with their own Radeon line. That would have been something worth using and talk about. Both in desktops and laptops.