HYDRA Driver and Performance
The HYDRA DriverWhen presented like this, the hardware part seems easy enough (though we know there are some impressive interactions going on under the hood). But anyone familiar with the world of multi-GPUs since the technology’s revival in the GeForce 6-series of graphics will be able to recount the horrors of driver incompatibilities, profiles, performance drops and instability that buffeted the multi-GPU solutions from both NVIDIA and ATI for quite a while. The HYDRA driver, though unique in how it works, will have to stand firm in the same winds.
In
terms of user interaction, the driver is pretty much painless and
option-less for now. You can see here that a simple check box either
enables or disables the HYDRA technology and there is no delay, reboot
or screen flashing involved in the process. This is how SLI/CrossFire
should be working!
The option to show the logo in the game allows you to have a HYDRA icon in the corner to prove HYDRA technology is working – though I imagine it would off by default in the final revision of the software.
The option to show the logo in the game allows you to have a HYDRA icon in the corner to prove HYDRA technology is working – though I imagine it would off by default in the final revision of the software.
You
can also choose to enable HYDRA on specific games or disable it if
there happens to be some kind of software glitch or incompatibility
that needs to be addressed down the road.
The
desktop tray icon allows you to easily enable/disable the HYDRA engine
though we are told the entire face of the software will likely change
in the next major revision.
Here you can see the icon that shows standard same-vendor HYDRA is in action.
And
this slightly different icon indicates that multi-vendor rendering is
at work here. Obviously this will be cleaned up for the final retail
release – that is really an awful font for this purpose!
Scenarios to Watch For
With the Lucid HYDRA technology there are going to be a metric ton of combinations to watch out for when it comes to performance testing and evaluation. Luckily for us, because we had very limited time with the hardware, we didn’t have much more than a few tons of testing and data to go through. Here is what you should be on the lookout from us today:
- HYDRA scaling with two identical GPUs
- HYDRA scaling with two non-identical GPUs from the same vendor
- HYDRA scaling with two GPUs from different vendors
Same Vendor Scaling (GTX 260+)
In this test we are going to be looking at same-vendor scaling using the GeForce GTX 260+ as the basis for our testing. You will see results from a single GeForce GTX 260+, a pair of GTX 260+ cards running HYDRA (not SLI, it was not an SLI-ready motherboard ironically enough) and the GTX 260+ paired with a GTX 285.
Starting
with the 3DMark Vantage results, you will see that the HYDRA scaling
method with the pair of GTX 260+ cards pushed performance up by 83% –
definitely a competitive solution to SLI! Considering the fact that
this motherboard, in its theoretical construction, didn’t have to pay
for any type of SLI licensing, I would say that THIS is the reason
NVIDIA might have put pressure on MSI to delay the Big Bang
motherboard.
In Call of Juarez the scaling going from a single card to dual cards was around 80% while on Far Cry 2 it was just over 51%. Both results are again pretty impressive.
When we take a look at the GTX 260+ combined with the GTX 285, the results are not what I initially expected. As most of you, I would assume that a configuration with a single GTX 260+ and a much more powerful GPU (the GTX 285) would produce a higher combined framerate than the pair of GTX 260+ graphics cards but that was not the case. Instead, the performance of the 260/285 combination happened to be nearly identical to the 260/260 results. Why is this?
Lucid tells us that the software based algorithms for separating workloads across identical GPUs differs greatly from the one required for load balancing with non-identical GPUs and thus scaling will in fact differ. There is some software overhead and load balancing overhead that has to take place and that costs us some performance. We had to assume this would be the case but it just kind of goes against standard logic: 2 + 2 = 4 but also 2 + 3 = 4 in the case.
In Call of Juarez the scaling going from a single card to dual cards was around 80% while on Far Cry 2 it was just over 51%. Both results are again pretty impressive.
When we take a look at the GTX 260+ combined with the GTX 285, the results are not what I initially expected. As most of you, I would assume that a configuration with a single GTX 260+ and a much more powerful GPU (the GTX 285) would produce a higher combined framerate than the pair of GTX 260+ graphics cards but that was not the case. Instead, the performance of the 260/285 combination happened to be nearly identical to the 260/260 results. Why is this?
Lucid tells us that the software based algorithms for separating workloads across identical GPUs differs greatly from the one required for load balancing with non-identical GPUs and thus scaling will in fact differ. There is some software overhead and load balancing overhead that has to take place and that costs us some performance. We had to assume this would be the case but it just kind of goes against standard logic: 2 + 2 = 4 but also 2 + 3 = 4 in the case.
Generational Scaling (GTX 285 -> GTS 250)
This series of tests expands on the results seen above by including individual results for the GTX 285 as a single card configuration as well as adding in a GTX 285 / GTS 250 combination in order to see scaling across more GPUs.
What
we see here is that in both games the GTX 285 + GTX 260 card
combination outperforms the GTX 285 + GTS 250 combination – proof that
the HYDRA engine is working as promised to at least some degree. That
difference is much more noticeable in the Call of Juarez DX10 testing:
adding a GTX 260+ to the GTX 285 nets us a 52% performance gain over
the single GTX 285 while combining it with the GTS 250 (a much lower
powered card) produces a 15% performance boost. In Far Cry 2 those
scaling percentages fall to 31% and 24% respectively.
So while the CoJ testing impresses us from a performance perspective and the Far Cry 2 performance does not, the fact is that the technology is indeed working in some titles.
So while the CoJ testing impresses us from a performance perspective and the Far Cry 2 performance does not, the fact is that the technology is indeed working in some titles.
This is where things can get even more interesting – combining an NVIDIA graphics card and an ATI graphics in a single system and seeing them work together, as nature (but not corporate executives) originally intended.
It works! In these two games you can see that simply put, the combined scores of the HD 4890 and GTX 260+ card are better than either individually. In the case of Call of Juarez the GTX 260+ adds another 40% or so to the gaming performance of the HD 4890 while in Operation Flashpoint the combined cards run about 33% faster than either individually.
What is important to note there is that the HYDRA technology will take the processing power of either GPU on any game and work to the best of its ability. Because on CoJ we saw that the HD 4890 was the better card individually, the GTX 260+ supplemented it. And in Operation Flashpoint the GTX 260+ was the better card going solo but the combination still allowed the HD 4890 to aid for better overall performance. In both cases, the “faster” card was able to save about 50% of the total performance of the “slower” card and add that into the gaming experience for the user.
