Windows 10 Meltdown/Spectre Patch Performance Impact Assessment

Introduction  

Over the past few days, it has been hard to see anything to do with PCs or computing without coming across the names Meltdown and Spectre, two recently discovered exploits that can be used to access protected data, potentially allowing hackers to steal data from programs running on a computer. 

Spectre has been found to be usable in most moderns processors, with Meltdown being seemingly exclusive to Intel (at least in the x86 market) due to architectural differences with AMD. The discovery of these bugs has prompted updates for every major computer operating system on the planet, with updates arriving for Windows 10 shortly after the issue became disclosed to the public. Fixes for both Windows 7 and 8 are also expected in the near future. 

Intel has been the worst hit by both Spectre and Meltdown, being affected by all three attack variants, with meltdown requiring some extreme software changes to mitigate the issue. Early estimates claimed that this fix would impose a 5-30% performance hit on Intel hardware, with today's testing being designed to showcase what kind of performance changes to expect. 

The software fix imposed by Microsoft is very similar to the fix introduced by into the Linux Kernel, though the performance impact of the change will vary depending on your system's workload and how often system memory needs to be accessed. 

More information about both Meltdown and Spectre is available here. 

Hardware Setup

To test the performance impact of this security fixing Windows Update, we will be using our games test system, which is based on Intel's X99 platform with an i7 6850K at 4.0GHz. In some of the tests, we will be using this CPU with all six CPU cores active, while others will be tested using both Dual-core and Hx-core configurations for reasons that will become clear later. 

Game Test Rig
Intel i7 6850K @4.0 GHz
ASUS X99 Strix
Corsair Vengeance LP 4x8GB DDR4 3200MHz
GTX 1080 Founders Edition
Corsair HX1200i
Corsair H110i GT
Windows 10 x64 "Creators Update"