How Xbox 2 (Project Scorpio) Runs Forza at 4K, 60FPS. Black Magic?

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Forza at 60fps 4k XBox 2

As part of the recent Xbox 2/Project Scorpio specs reveal, new details were also revealed that claimed Forza was running on Xbox 2 with a 4K resolution and 60FPS gameplay! That kind of performance doesn’t come easily, even on PC. How the heck did Microsoft get a console to do it?

It’s a combination of innovation, research, and probably a bit of black magic, but that last one is pure speculation. Join us as we look at the process behind this incredible gaming milestone!

The Secret Behind Forza’s 4K Performance on Xbox Two (Project Scorpio)

When the Xbox 2/Project Scorpio specs were officially revealed by Eurogamer, some new information came to light. Microsoft had been developing and using a tool they called PIX, which stands for “Performance Investigator for Xbox.”

The purpose of the tool, was to perform GPU trace capture. They used it to analyze titles with the goal of running any 900p or better game in 4K at a strong frame rate on Scorpio. This was all part of their highly customized approach to designing the system’s specs.

Normally, developers have to work within the confines of the console, but Scorpio/Xbox 2 has the unique benefit of scaling existing games up to 4K. This meant that they hardware team could use existing titles to customize the design of the new console.

Using data from the PIX tool, Microsoft could feed this information into a hardware emulator that allowed them to test multiple hardware configurations at once. According to a member of the team, Andrew Goossen:

XBox 2 4k“Now we had a model for all of our top-selling Xbox One games where we could tweak the configuration for the number of CUs, the clock, the memory bandwidth, the number of render back-ends, the number of shader engines, and the cache size. We could figure out what was the most optimal configuration. It was incredibly valuable for us to be able to make those trade-offs, because ultimately these Xbox One titles are the ones that we wanted to get up to 4K.”

Specifically, the team at Turn 10 were able to tweak the game’s engine as well to equally adapt to Scorpio’s hardware. Chris Tector, Studio Software Architect at Turn 10 Studios also spoke with Eurogamer about how they were able to accomplish this feat.

While the PIX tool was used to help shape the processor through data gathered by current titles, Turn 10 was also able to use their engine, known as ForzaTech, to make modifications on their end and take advantage of the new hardware. As Chris explains:

”We provided a ton of data with ForzaTech, where we actually rendered different stress scenes at different resolutions (720p, 1080p, 4K), and then stressed different points in the engine: anisotropic filtering, multi-sampling, pushing heavy LODs through, just to try and get a feel for where the different bottlenecks were.”

The profiling data that Turn 10 provided was invaluable to the hardware design of Xbox 2/Project Scorpio. Other titles were also providing input as well, which fueled the success of the PIX tool.

So, after all of this work, how did it pan out?

The Results: Ultra Settings, 4K Resolution, 60FPS

When it came time to get something running on prospective Scorpio hardware, it came down to Matt Lee from the Xbox Direct3D team to put something together. At this point, they didn’t have anything resembling a console:

”He had a cardboard box full of parts and he starts getting them out on the desk and it’s all loose motherboards, nothing’s fitting together, it’s debug connectors and it doesn’t even have the proper cooling. So, there’s this huge PC fan and it’s just sitting on the desk blowing across the top of it.”

It took a mere two days to get ForzaTech running on Project Scorpio/Xbox 2 hardware. According to Chris Tector, it was mostly spend adapting the codebase. They had a small issue surrounding memory alignment, but otherwise, the engine transferred smoothly over to the new hardware. By the time they had reached the third day, they were testing out graphical options and doing stress tests.

Not only were they able to demonstrate a native 4K resolution and 60FPS, but they were also able to push through 4K textures as well. Turn 10 was running the game on Ultra settings, with the resolution and frame rate stable. They had GPU power to spare at this point, which allowed them to push the game above the PC ultra settings for everything related to the GPU.

Even at this, they were running at 88% of the GPU’s full potential. Things like shadow quality, foliage density, and motion blur quality all skyrocket. Eurogamer’s estimates compare this level of performance to the Nvidia GTX 1070 GPU, and even that video card can drop frames at ultra settings.

Turn 10 has a very strict budgeting system for their engine, which keeps everything in balance, so this doesn’t happen on their Scorpio/Xbox 2 demo build that they showed Eurogamer. While they can pump up the graphics and really push the GPU, that’s not the point here.

Instead, we’re seeing a future where developers don’t have to wonder how they’ll hit their frame rate and resolution goals. Instead, they can focus on improving the image quality and the overall quality of the game.

Tector puts it perfectly:

”The awesome part about the whole story, is that we can spend all this time heading into the future. Instead of saying ‘how are we going to wrestle to get the performance on this,’ we’re actually saying we can make this quality trade-off or this quality trade-off and spend that time iterating towards much better image quality. So, instead of stressing about getting to a final resolution for titles, or a final frame-rate, we can really drive it all into quality.”

Turn 10’s ForzaTech is one of the best engines in the industry, but the level of performance we’ve seen here shows a great first impression for Scorpio/Xbox 2 hardware. The real question is, how will other engines fare on the new hardware? Can we expect the same level of performance?

It’s too early to say, but Microsoft’s official stance, is that developers have had varying degrees of results, but all have been positive thus far. What do you think of these results? What kind of improvements would you like to see with the extra horsepower? Let us know in the comments!

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