Microsoft has just issued a new September firmware update for the Surface Pro 3. The primary fix for this update is a USB 3.0 card reader driver update (v10.0.10240.31217) which is supposed to improve power efficiency when using an attached SD card.
Many users familiar with the Haswell-based Surface Pros (Surface Pro 2 and Pro 3) may know of a persistent issue that plagues some unlucky devices, where a system process called System Interrupt constantly monopolizes about 30 percent of overall CPU utilization even during idle, devastating battery life and driving heat output through the roof for no reason. This issue is well-documented throughout Microsoft’s user support questions and various Surface communities such as r/Surface, but Microsoft has never adequately addressed this issue for the entire span of two generations of Surface devices.
No one knows the exact cause of this issue, but documented instances show a strong correlation with SD card usage. It may also be related to the device’s audio subsystems, as a bizarre and temporary remedy to this problem is to play any form of persistent audio (such as music through Windows Media Player). Currently known remedies include the audio trick, as well as resetting the computer. However, afflicted devices will only be relieved temporarily, as shutting down the computer via Shut Down will cause the problem to resume on next startup. Changing hybrid boot settings are not known to alter this behavior.
It remains to be seen whether this firmware update fixes the problem, or if this is the problem the firmware update is even trying to address, as to my knowledge Microsoft has never publically acknowledged this issue, though there’s no doubt the company is aware of it.
Getting this update is easy as can be, as it should be installed automatically through Windows Update, or notify you if you have it configured such. If not, be sure to manually check for it via Windows Update.Further reading: Firmware, Surface, Surface Pro 2, Surface Pro 3, update