It's not directly published in the product specifications but if you look at Table 1-1 for the virtual appliance (here) it refers to the physical appliance as having characteristics thus:
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High End Virtual Appliance supports the same number of managed devices as a Physical Appliance (PRIME-NCS-APL-K9).
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Supports up to 15000 Cisco Aironet lightweight access points, 5000 autonomous access points, 5000 switches and 1200 Cisco wireless LAN controllers.
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Processors: 8, at 2.93 GHz or better.
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Minimum RAM:16 GB.
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Minimum hard disk space allocation: 400 GB