A Spymac thread posted this weekend reveals some screenshots and information about a feature of the new PowerMac G5's called "Slewing".
The feature is located in the Energy Saver Control Panel and allows the user to make some modifications to the Processor and Bus performance settings. A concept that is familiar to laptop owners... the G5 can be run in Reduced, Highest and Automatic performance settings.
To lower power consumption, heat generation, and fan noise, the Power Mac G5 computer incorporates an automatic power management technique called bus slewing. Bus slewing is designed to run at high processor and bus speeds and high voltage when the demand on the processor is high, and to run at low processor and bus speeds and low voltage when the demand on the processor is low.
Speed ranges involved start from 1.3GHz up to the highest rated GHz of the chip (1.6, 1.8, or 2.0). The default slewing option for the PowerMac G5s is Automatic, and the processor and bus speeds are modulated seamlessly to the user.
According to our contacts, there should be no performance loss in Automatic mode.
That being said, at least one user (in the previously mentioned thread) claims an 11 point increase in their Xbench score after changing their Slewing mode from Automatic to Highest. However, readers are reminded that XBench has been inconsistent in producing reproducible benchmark numbers -- even on the same machine. MacRumors' reader 1stunna managed to get a 11 point increase in Xbench scores by simply rerunning the test three times, with no other changes to the system. Whether this represents test-to-test variability or a side-effect of the processor automatically ramping up is still up for debate.
The ramp time up or down is ~1ms, but the CPU is running normally during this time, so there is no performance "hiccup". This results in about 60% power/heat savings, which jumps up to about 85% savings if the machine is idle and they "turn on other power saving features". When idle, the CPU fans are barely turning.
Monday December 1, 2025 4:37 pm PST by Juli Clover
We're getting closer to the launch of the final major iOS update of the year, with Apple set to release iOS 26.2 in December. We've had three betas so far and are expecting a fourth beta or a release candidate this week, so a launch could follow as soon as next week.
Past Launch Dates
Apple's past iOS x.2 updates from the last few years have all happened right around the middle of the...
Tuesday December 2, 2025 11:09 am PST by Juli Clover
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent.
Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
Monday December 1, 2025 3:00 am PST by Tim Hardwick
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device.
Subscribe to the MacRumors YouTube channel for more videos.
Below, we've collated an updated set of key details that ...
Tuesday December 2, 2025 9:44 am PST by Juli Clover
Apple's iPhone 17 lineup is selling well enough that Apple is on track to ship more than 247.4 million total iPhones in 2025, according to a new report from IDC.
Total 2025 shipments are forecast to grow 6.1 percent year over year due to iPhone 17 demand and increased sales in China, a major market for Apple.
Overall worldwide smartphone shipments across Android and iOS are forecast to...
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Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....
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2026 could be a bumper year for Apple's Mac lineup, with the company expected to announce as many as four separate MacBook launches. Rumors suggest Apple will court both ends of the consumer spectrum, with more affordable options for students and feature-rich premium lines for users that seek the highest specifications from a laptop.
Below is a breakdown of what we're expecting over the next ...
Thursday December 4, 2025 9:30 am PST by Joe Rossignol
In a statement shared with Bloomberg on Wednesday, Apple confirmed that its software design chief Alan Dye will be leaving. Apple said Dye will be succeeded by Stephen Lemay, who has been a software designer at the company since 1999.
Meta CEO Mark Zuckerberg announced that Dye will lead a new creative studio within the company's AR/VR division Reality Labs.
On his blog Daring Fireball,...
The iPhone Air has recorded the steepest early resale value drop of any iPhone model in years, with new data showing that several configurations have lost almost 50% of their value within ten weeks of launch.
According to a ten-week analysis published by SellCell, Apple's latest lineup is showing a pronounced split in resale performance between the iPhone 17 models and the iPhone Air....
Tuesday December 2, 2025 3:30 pm PST by Juli Clover
OpenAI is deprioritizing work on advertising as it focuses on improving the quality of ChatGPT, reports The Information. OpenAI CEO Sam Altman declared a "code red" on Monday, and told employees that the company needs to improve ChatGPT so it doesn't fall behind competitors like Google and Anthropic.
Altman said that OpenAI needs to work on personalization for each user, image generation,...
Monday December 1, 2025 2:16 pm PST by Juli Clover
Apple AI chief John Giannandrea is stepping down from his position and retiring in spring 2026, Apple announced today.
Giannandrea will serve as an advisor between now and 2026, with former Microsoft AI researcher Amar Subramanya set to take over as vice president of AI. Subramanya will report to Apple engineering chief Craig Federighi, and will lead Apple Foundation Models, ML research, and ...
