Back in the day it was all about FRAPS. These days, Riva Tuner Statistics Server and OCAT are the tools of choice. For decades now, PC users have relied on real-time on-screen displays with frame-rate counters and system monitoring tools to give them some idea of how their PCs are being utilised during gaming. But what if similar tools were available to console users? Remarkably, a recent breakthrough in Switch modding has made this a reality. Frame-rates, CPU/GPU utilisation, temperature monitors, fan speeds: all are exposed, giving us a fascinating insight into how Switch titles pushe the hardware during gaming.
Of course, this is all limited to earlier Switch revisions, vulnerable to a recovery mode hardware exploit on which custom firmware was developed. Yes, you can run these tools yourself but there is a route to piracy here – so not surprisingly, consoles attached to Nintendo’s online gaming service are routinely banned. But the interesting part from the Digital Foundry perspective is the flourishing homebrew environment, which recently saw the release of the Tesla frame-work – code that runs on the Switch’s reserved CPU core, bringing up an interactive overlay at any time during gaming. Tesla was swifty followed by the release of the Switch overlay mod, which essentially builds much of Riva Tuner Statistics Server’s functionality onto the Tesla foundation. Voila: full real-time system analysis – but what does it reveal?
Well, at the most basic level, you get instant confirmation that Nintendo does indeed reserve one of the Switch’s CPU cores for the OS and front-end – the overlay shows cores zero to two essentially dormant while navigating the shell, with only core three active as the menus are traversed. Similarly, there’s on-screen confirmation that Switch’s docked clocks are totally locked during gameplay: 1020MHz for the CPU, 768MHz for the GPU, 1600MHz on the EMC (embedded memory controller).
However, there is a twist and it’s something we’ve covered before, that we can now see play out in real-time – Nintendo’s ‘boost mode’. This amounts to optimisations in how certain games selectively overclock the CPU to improve loading times. For example, when you die in Mario Odyssey, the screen fades to black and the game loads you back to the last checkpoint. There is a fairly quick turnaround in Odyssey but this is faster thanks to boost mode. During loading, the CPU gets upclocked temporarily to 1785MHz – a 75 per cent increase on the stock clock. Meanwhile, the GPU actually drops all the way down to 76.8MHz – a tenth of its usual speed. Nintendo is balancing thermals by overclocking one component to the max, while downclocking another to the bare minimum.
This technique is used in plenty of modern titles: Wolfenstein Youngblood, and even Crash Team Racing take advantage, while Zelda: Breath of the Wild and Super Mario Odyssey were patched to include it. Loading times are predicated not just on the speed of the internal NAND storage or your SD card, but also on the CPU decompressing assets in the background. With the screen being blank or static, there’s no need to have the graphics processing running at full power anyway. At least, not for this moment. At the first sign of gameplay, the Switch reverts back to default clocks. Boost mode certainly does the trick – I noticed around seven seconds lopped off the loading time from the main menu to the Great Plateau in Breath of the Wild – 23 seconds vs 30 seconds.