The first tech deep dive from Sony and Marc Cerny for the PS5 in March has sparked lively discussions since then. As a result, and in comparison to the Xbox Series X, it now seems clear that Sony tends to rely on a special custom solution, while Microsoft uses standardized components just to achieve more performance.
How much this ultimately affects the individual games and whether the Xbox Series X is actually so superior as it looks on paper is still completely unclear. According to another tech Reviews, which comes from conversations with Marc Cerny, it looks as if Sony with its custom solution is more suited to the developers, especially when it comes to the optimization effort.
Today one writes:
“In a nutshell, the idea is that developers can learn to optimize in other ways by getting identical results from the GPU, but faster with higher clocks provided by optimizing power consumption. The CPU and GPU each have a power budget, and of course the GPU power budget is the larger of the two, ”said Cerny. “If the CPU does not use its performance budget – for example if it is limited to 3.5 GHz – the unused part of the budget goes to the GPU. This is what AMD calls SmartShift. There is enough power to potentially run the CPU and GPU at their 3.5Ghz and 2.23Ghz limits, but if not, the developers can choose to run them lower. ”
Another phenomenon is called “Race to Idle” and is described as follows:
“We work at 30 Hz and use 28 milliseconds from our 33 millisecond budget, so the GPU is idle for five milliseconds. The power control logic will determine that little power is being consumed – after all, the GPU doesn’t do much in these five milliseconds – and conclude that the frequency should be increased. But that’s a pointless frequency increase. ”
In summary, this means that the clock rate can usually be much higher, but in Cerny’s eyes this seems useless.
“The result is that the GPU no longer does any work, but processes its assigned work faster, is idle for longer, and is just waiting for V-Sync or something similar. We use ‘Race to Idle’ to describe that this is a pointless increase in GPU frequency. ”
This approach does a lot of the optimization work for developers, or as Cerny described: “It is much easier to fully optimize and use 36 compute units in parallel than to properly optimize 52 compute units in the same way.”
Ultimately, however, much is still unclear how this boost function will later affect the game design. According to Digital Foundry, several developers have indicated that they are throttling the CPU due to their current work on the PS5 to ensure a permanent 2.23 GHz clock on the graphics core. This seems reasonable because most game engines are currently designed for lower performance. Even doubling to 60fps would currently hardly burden the Zen 2 cores of the PS5, it is said.
The colleagues from Eurogamer and Digital Foundry have the full article on deep diving.
