Performance and Memory issues with Windows 11

Dear Tcl/Tk group,
is anybody aware of any issues with Windows 11?
I updated my laptop from Windows 10 to Windows 11 and all Tcl programs feel 10 times slower.
They are apparently waiting for something I don't know.
A client reports of an error box "unable to realloc 90500 bytes" which apprears after a day of not using the program.
This is TCL 8.6.16 (or 8.6.13 in the client case) compiled with MS-VC6.
I know, the move to TCL 9 and a more recent compiler is pending.
Does anybody has an idea here?
Thanks for all,
Harald