2019 Windows update may address Spectre patch-related performance issues

Windows 10 19H1 is a pending update for the OS that is likely to be released next year. Recently, some users running it on devices as part of the Windows Insider Preview program have found that their performance is not suffering as a result of patches for the potential Spectre and Meltdown exploits as it might have in older Win10 versions.

This is being put down to the new adaptation known as Retpoline (or 'Return Trampoline'), which was originally devised by Paul Turner for Google. It is a kernel developed shortly after the discovery of the two major CVEs. Retpoline is designed to deal with the second variant of Spectre, which is viewed as more insidious by those in the cybersecurity arena. 

Retpoline reportedly patches Spectre 2-prone speculative execution in a more indirect manner compared to other patches. According to Microsoft developers such as Mehmet Iyigun, it reduces the potential impact on performance to the level of "background noise". This is done through an implementation of Retpoline called "Import Optimization". 

Alex Ionescu, who tested 19H1 on his Surface Pro 4, reported that this resulted in improved transfer rates, particularly at "smaller block sizes". Therefore, this Windows 10 update may be able to alleviate the performance detriments (which have been reported to be as high as 30%) associated with the Spectre-patching of the past, 

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