The documentation is correct.
From the 4.6 Architecture & Planning guide it says:
Security servers with PCoIP support run on Windows Server 2008 R2 and take full advantage of the 64-bit architecture. This security server can also take advantage of Intel processors that support AES New Instructions (AESNI) for highly optimized PCoIP encryption and decryption performance.
When installing View 4.6 Connection Server/Security Server you should have got a warning popup about this if you were using a different operating system version.
Mark.