At least 512 MB (though 2 GB+ is recommended for stable performance).
Before downloading, ensure your server meets these minimum specifications to avoid installation errors: At least 512 MB (though 2 GB+ is
Approximately 1,500 MB of free hard drive space. At least 512 MB (though 2 GB+ is
Windows Server 2008 R2 Standard, Enterprise, or Foundation (Service Pack 1 or later). Processor: 64-bit (x64) at 1.4 GHz or higher. At least 512 MB (though 2 GB+ is
Microsoft Windows Installer 3.1 and .NET Framework 4.0 or later must be installed. How to Download and Install Hardware and software requirements - Kaspersky Support
Hardware and software requirements * 920 MB free disk space on the hard drive. * Processor that supports the SSE2 instruction set. Hardware and software requirements - Kaspersky support