The return of the turbo button: New Intel hotness causes an old friend to reappear

Finally – a purpose for the least-used key on your keyboard

Do you remember the days before desktop processors needed heatsinks? Are you wearied by the constant churn of new computer tech that never seems to make things easier?

Intel has good news for you: it's bringing back an old friend: the turbo button.

Better still, you won't need any new hardware, because it's repurposing something you already have but never use: your Scroll Lock key.

Grey-haired techies may remember that the turbo button didn't do what it said on the tin. It didn't magically make a sluggish PC faster, but rather the reverse: it slowed it down to make older programs – games, mainly, that weren't designed for 33 screaming megahertz of raw 486 power – playable again. Well, it's games to blame again now that Intel's 12th generation of Core processors is here.

Chipzilla emitted a troubleshooting bulletin recommending the use of Scroll Lock as a workaround yesterday, prompting more than one person to comment that this made Scroll Lock the new turbo button.

(If you have lost track of the generations, we don't blame you. So far, they were: Nehalem; Sandy Bridge; Ivy Bridge; Haswell; Broadwell; Skylake; Kaby Lake; Coffee, Amber, Whiskey and Cannon Lake; Cascade, Ice and Comet Lake; Tiger and Rocket Lake. And now, Alder Lake. Clear as Shenzhen lake-bottom mud.)

Naturally Intel is saying its latest PC silicon is the fastest thing ever, but the big change in this generation is really about power management.

Alder Lake is Intel's second go at what it initially called "hybrid technology" CPUs. Alder Lake chips have a blend of ­two types of processor core: some high-performance but electricity-hungry, and some Atom-style – lower-performance but frugal with the juice.

This style of design was pioneered a decade ago by Arm, which called it big.LITTLE, much to the chagrin of The Reg's correspondent. It's useful for smartphones and tablets alike – so long as the OS knows about it, it can shuffle tasks around between performance or efficiency cores depending on available battery life, cooling, user demands and so on. It's also good for marketroids, who can claim that a chip with, say, three of each type is a "six-core" device.

Apple's new Arm-based chips have their own versions of the same tech, naturally, and Apple has been rather cunning about how it spreads the load.

The problem is that this stuff is new to PCs. PCs with low-power Atom chippery arrived in 2008 for netbooks and so on. The processors were sold on being cheap, small, and having decent battery life – not on their rapidity, because they didn't have any. Now Intel's mixing together low-end Atom-class cores and high-performance normal cores in the same microprocessor package to balance power usage and oomph, which is most useful in laptops and tablets.

That is to say, a lot of PC-grade programs don't expect the CPU cores available on a system to dynamically change in type: a quad-core system in the past has four cores of the same type, not a combination of different ones powered up as the OS desires.

Some software, particularly games, check the specification of the PC to not only ensure it has enough oomph to run the title but also to see if the hardware underneath has changed, which is a sign the program has been pirated to another system.

It so happens that a shiny new 12th-gen Intel Core processor can trip up the anti-copy protection, or DRM, in games, presumably by presenting its Atom-class and performance-grade cores in such a way that the anti-piracy code thinks the game is being run on another PC. It's either that, or the hybrid nature of the microprocessor upsets the DRM code enough to make titles crash out or fail to load.

This apparently affects a bunch of games on Windows 10 and 11, at least, that use the Denuvo DRM tookit. Some patches are due to arrive in mid-November to correct these crashes.

In the meantime, enter the 21st century turbo button. All the lucky new owner of one of these boxes has to do, if they are experiencing problems with their games, is go into the system firmware, enable the Legacy Game Compatibility Mode option, reboot, and then, when you press Scroll Lock, your PC will gently anesthetize its efficiency cores. Result? The game and its copy-protection will only see the high-performance ones and work fine.

In other words, the newly repurposed key actually turns off the whizz-bang hybrid-chip feature – a little like the way a 1980s turbo button actually slowed your CPU down so you could play Alley Cat or Maniac Mansion. Technology: innit marvelous, eh? ®