32-bit system error or x64 instance of MariaDB

So I've installed MariaDB in x64 version on my Windows Server (which also is x64 and has 10GB of RAM memory available), yet when I adjust innodb_buffer_pool_size variable to over 4GB I get the:

[ERROR] innobase_buffer_pool_size can't be over 4GB on 32-bit systems

I most definitely used the https://downloads.mariadb.org/interstitial/mariadb-10.1.19/winx64-packages/mariadb-10.1.19-winx64.msi/from/http%3A//mariadb.kisiek.net/ installer.

Windows Control Panel indicates MariaDB is in x64 version, also mysql --version command returns:
C:\xampp\mysql\bin>mysql --version
mysql Ver 15.1 Distrib 10.1.19-MariaDB, for Win32 (AMD64)

The one thing that might be important is that while installing this version I've overwritten default XAMPP MySQL instance, which is x86.

Any clues?