R help - Aug 2025 - Bug Report: R for Windows installer fails to enable Intel MKL on modern hardware

Dear R Core Development Team,

I am writing to report a potential issue with the standard R installer for
Windows. On modern, high-performance hardware, the installer does not
appear to be automatically enabling the Intel Math Kernel Library (MKL) as
expected, defaulting instead to the standard, single-threaded BLAS/LAPACK
libraries.

Here are the details of my system and the steps to reproduce the issue:

*1. System Information*

   -

   *Hardware:* Lenovo Legion Pro 5 Laptop
   -

   *Operating System:* Windows 11 x64 (build 26100)
   -

   *R Version:* R version 4.5.1 (2025-06-13 ucrt)
   -

   *sessionInfo() Output:*

   R version 4.5.1 (2025-06-13 ucrt)
   Platform: x86_64-w64-mingw32/x64
   Running under: Windows 11 x64 (build 26100)

   Matrix products: default
     LAPACK version 3.12.1

   locale:
   [1] LC_COLLATE=English_United States.utf8
   [2] LC_CTYPE=English_United States.utf8
   [3] LC_MONETARY=English_United States.utf8
   [4] LC_NUMERIC=C
   [5] LC_TIME=English_United States.utf8


*2. Steps to Reproduce*

   1.

   Performed a clean uninstall of any previous R versions.
   2.

   Downloaded the latest R installer from the official CRAN mirror:
   https://cran.r-project.org/bin/windows/base/.
   3.

   Ran the installer using the standard, default settings.
   4.

   Opened R and ran the sessionInfo() command to check the linked math
   libraries.

*3. Expected Result* I expected the sessionInfo() output to show a
reference to mkl_rt.dll in the LAPACK line, confirming that the
high-performance, multi-threaded MKL was active.

*4. Actual Result* The sessionInfo() output shows Matrix products: default
and LAPACK version 3.12.1, with no mention of MKL. This indicates that the
standard, slower libraries were installed. This significantly impacts
performance for computationally intensive tasks like PCA on large matrices.

Thank you for your incredible work on R. I hope this report is helpful in
improving the installation experience on Windows. Please let me know if any
further information or testing would be useful.

Sincerely,

[Your Name]

	[[alternative HTML version deleted]]

On 04.08.2025 19:29, mo. sadik khan wrote:
> Dear R Core Development Team,
> 
> I am writing to report a potential issue with the standard R installer for
> Windows. On modern, high-performance hardware, the installer does not
> appear to be automatically enabling the Intel Math Kernel Library (MKL) as
> expected, defaulting instead to the standard, single-threaded BLAS/LAPACK
> libraries.
Yes. Whch documentation tells you it would do so automatically?

Best,
Uwe Ligges


> 
> Here are the details of my system and the steps to reproduce the issue:
> 
> *1. System Information*
> 
>     -
> 
>     *Hardware:* Lenovo Legion Pro 5 Laptop
>     -
> 
>     *Operating System:* Windows 11 x64 (build 26100)
>     -
> 
>     *R Version:* R version 4.5.1 (2025-06-13 ucrt)
>     -
> 
>     *sessionInfo() Output:*
> 
>     R version 4.5.1 (2025-06-13 ucrt)
>     Platform: x86_64-w64-mingw32/x64
>     Running under: Windows 11 x64 (build 26100)
> 
>     Matrix products: default
>       LAPACK version 3.12.1
> 
>     locale:
>     [1] LC_COLLATE=English_United States.utf8
>     [2] LC_CTYPE=English_United States.utf8
>     [3] LC_MONETARY=English_United States.utf8
>     [4] LC_NUMERIC=C
>     [5] LC_TIME=English_United States.utf8
> 
> 
> *2. Steps to Reproduce*
> 
>     1.
> 
>     Performed a clean uninstall of any previous R versions.
>     2.
> 
>     Downloaded the latest R installer from the official CRAN mirror:
>     https://cran.r-project.org/bin/windows/base/.
>     3.
> 
>     Ran the installer using the standard, default settings.
>     4.
> 
>     Opened R and ran the sessionInfo() command to check the linked math
>     libraries.
> 
> *3. Expected Result* I expected the sessionInfo() output to show a
> reference to mkl_rt.dll in the LAPACK line, confirming that the
> high-performance, multi-threaded MKL was active.
> 
> *4. Actual Result* The sessionInfo() output shows Matrix products: default
> and LAPACK version 3.12.1, with no mention of MKL. This indicates that the
> standard, slower libraries were installed. This significantly impacts
> performance for computationally intensive tasks like PCA on large matrices.
> 
> Thank you for your incredible work on R. I hope this report is helpful in
> improving the installation experience on Windows. Please let me know if any
> further information or testing would be useful.
> 
> Sincerely,
> 
> [Your Name]
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
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