Yes, to use the 450MHz part for any frequency, the SVSnominal method need to be used.
The Static Voltage Scaling (SVS) is an alternate voltage specification technique that can provide significant performance benefits including higher frequency operation without a major increase in power consumption. That said, Static Voltage Scaling is only available on parts specifically designed for SVS operation.
Please refer the application note(EE-357) which talks about "Static Voltage Scaling for ADSP-2148x SHARC Processors" for operating ADSP-2148x processors at 450MHz. The link is given below.
https://www.analog.com/media/en/technical-documentation/application-notes/EE357.pdf