The 15-inch Retina MacBook Pro has been touted as the highest-resolution laptop available for purchase, and plenty of consumers have jumped all over it despite its relative size and substantial price premium over Apple’s non-Retina offerings.
However, not all is well and good for users of the impressive laptop. AppleInsider reports that after updating their machines to the latest version of its extensible firmware interface (EFI), some users have complained of palpable dips in GPU and CPU performance that have manifested themselves through visible slowdowns in frame rates.
The issue has been attributed to thermal throttling of either the GPU, the CPU or both when temperatures reach certain thresholds that seem overly conservative. For instance, reaching 65 to 70 degrees Celsius will lead the system to clock down the graphics 150MHz to 700MHz, with commensurate additional throttling at higher temperatures.
The biggest oddity about the entire situation is the fact that Intel lists the specific CPU found in the Retina MacBook Pro with a maximum operating temperature of 105 degrees Celsius. Typically referred to as the Tjunction maximum or TjMax value, it is at this threshold that the CPU will automatically start clocking itself down to prevent permanent damage due to temperature.
Even considering that lower temperatures are typically a good thing, the resulting dropdown in graphics capabilities may simply be too much of a cost for users, especially if the temperatures are nowhere near the maximum rating of the CPU.
Users of affected Retina MacBook Pros say that resetting the SMC or flashing the PRAM may serve as a temporary fix to the problem, but the issue still crops up under a range of circumstances, including waking from sleep.










