MultiGPU Update: Finding the True Halo with 4-way

Who Scales ... And Timing

In previous articles, we took a look at some stats on how many tests scale more or less than a certain threshold. Well, it gets a little trickier here to make sense of everything, so rather than pick points ourselves, we decided to list a bunch of them. In the chart below, we've listed the number of tests that fail to scale better than the percentage listed at the top of the column. Lots of tests fail to scale at what we would call a reasonable percentage, but people looking at these parts have a different definition of reasonable.

The maximum scaling percent is 100% just like with scaling from 1 to 2 GPU. But fewer games scale past 2 GPUs, and of those that do, fewer scale as near linearly past 2 GPUs. And to top that off, many tests that do scale at all scale right into a system limitation. A good chunk of games fail to scale past 5%, and fully 13 out of 18 tests fail to scale beyond 50% in each case we tested.

Looking at the lower end we can see a bunch of tests fail to scale at all. Also, at 33%, many fewer situations scale at this rate than when moving from 1 to 2 GPUs. Clearly 4-way multiGPU solutions are not designed with anything but maximum performance in mind. Scaling isn't as important as the fact that these solutions can provide some degree of higher performance in some situations.

We would also like to note that when paying ridiculous amounts of money for not quite as ridiculous performance gains, the robustness of the solution is of very high importance. No one wants to pay over $1000 and get a solution that sometimes provides good scaling and sometimes degrades performance. Neither AMD nor NVIDIA are immune to this, but we would like to see this issue tackled in more earnest beyond simply noting that SLI and CrossFire can be disabled if trouble arises.

NVIDIA does have an advantage at this level though. We would love to see AMD get their driver act together and consistently have drivers that provide good scaling and performance in newly release AAA titles on launch day. We would also love to see them refine their driver development model in order to make sure that improvements released as hotfixes always make it into the very next WHQL driver released (which is currently not the case). Everywhere else, this is merely a slight annoyance that people may take or leave. At the highest of the high end, however, a delay in getting good scaling or the need to use less recent drivers that contain more recent fixes (and juggling which is which) can prove more than just a trifle. For such a high price, NVIDIA delivers a better experience on this count.

Additionally, until OpenCL matures, CUDA is a better GPU computing alternative to what AMD offers, and PhysX can provide additional flexibility now that more titles are beginning to adopt it. Actually, this is the space in which we currently see the most value in CUDA and PhysX, as those in the market for equipment this high end will be more interested in these niche features that don't have broad enough support or large enough current impact for us to heartily recommend them as a must have for everyone.

Technophiles (like myself) that are willing to put this kind of money into hardware often get excited about the hardware on a more than practical level. The technology itself, rather than the experience it delivers, can often be a source of enjoyment for the end user. I know I like playing with PhysX and CUDA in spite of the fact that these technologies still need broader support to compel the average gamer.

Performance, itself, cannot be ignored, and is indeed of the highest importance when it comes to the highest end configurations. We will include the value graphs, but we expect that the line closest to the top of the performance charts are the key factor in decision making when it comes to Quad GPU options. The troubles that come with maintaining a 4 GPU configuration are not worth it if the system doesn't provide a consistently top of the line experience.