Microsoft’s KB5007215 update doesn’t entirely fix the AMD Ryzen L3 cache issue

This is Microsoft's second attempt (after KB5006746). Do we have to wait for third time lucky?


Last month, Microsoft released the KB5006746 patch for Windows 11, which sought to address performance issues with AMD Ryzen L3 cache usage, among a long list of fixes. This, and the UEFI CPPC2 “preferred core” update delivered by AMD via a new chipset driver, was supposed to fix the Ryzen performance of Windows 11, particularly in gaming applications which appear to have been worst affected.

However, with KB5006746 in place, the AMD Ryzen L3 cache still didn’t perform as well as it did when tested under Windows 10. Latency and throughput were definitely improved, but could obviously be better, as they were better in the older OS. Now reports that Microsoft has rolled out another Windows 11 update, KB5007215, which includes further L3 cache tuning but “does not completely fix” the issues.

Caching is hugely important for processor performance

The German-language source says that KB5007215 has helped somewhat, but even with this patch applied, Windows 10 remains superior in terms of L3 cache performance. To back up its claims, has provided some AIDA64 testing screenshots. You can head on over to the source link to check those out; we’ve just reproduced the collated results table for ease of comparison, below.

L3-cache testWindows 11 Pass 1Pass 2Pass 3Pass 4Windows 10
Read throughput438GB/s723GB/s696GB/s777GB/s1,047GB/s
Write throughput578GB/s504GB/s176GB/s261GB/s680GB/s
Copy throughput218GB/s203GB/s689GB/s681GB/s912GB/s
Test results from

Another thing you will see from the results table above is that Windows 11’s L3 cache performance is rather inconsistent, represented by the four passes. Heise asserts that Windows 10 churned out the same numbers in multiple passes with “minimal fluctuations,” hence the single column of results for the older OS.

The Club386 editor is going to be looking at Intel Alder Lake performance differences across Windows 10 and 11 shortly, so please stay tuned for that in-depth assessment of the remaining differences/issues.