Windows 10 gave Win32 apps including Chrome access to a ‘segment heap’ API to allow apps to reduce memory usage.

However, Chromium engineers have decided for now to turn off the feature by default in Chrome 85 after discovering it caused a hit on the CPU.

The CPU issue was discovered by an Intel engineer who found that when Chrome used segment heap, it led to significant performance regression in benchmarks on a PC with an Intel Core i9-9900K processor.

Microsoft has defended the trade-off between memory and CPU but conceded it could be implemented better to reduce the impact on CPU performance.

“It is common practice to trade one resource for another. More often it’s increased memory usage for reduced CPU usage. In this case, it’s increased CPU usage for dramatically reduced memory usage, or more accurately commit”, wrote a Microsoft employee.

“In the short term this is a good trade-off of one resource for another as memory/commit usage is a significant pain point for browser users”, argued the Volish employee.

The CPU cost appeared to be a 10 percent slowdown on Speedometer 2.0 and a 13 percent increase in CPU/power consumption.