The AMD Platform Security Processor (PSP), officially known as AMD Secure Technology, is a trusted execution environment subsystem incorporated since about 2013 into AMD microprocessors
[1] According to an AMD developer's guide, the subsystem is "responsible for creating, monitoring and maintaining the security environment" and "its functions include managing the boot process, initializing various security related mechanisms, and monitoring the system for any suspicious activity or events and implementing an appropriate response"
[2] Critics worry it can be used as a backdoor and is a security concern
[3][4][5] AMD has denied requests to open source the code that runs on the PSP

Since about 2013

processor predating this are the Opteron series 4100 to 6100 with the best specs

Valid cpus:
AMD Opteron 4284 - eight core 3ghz - 2010
AMD Opteron 6220 - eight core 3ghz - 2011
AMD Opteron 6238 - twelve core 2.6ghz - 2011

Cost 12 - 50 eur

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wiki links with opterons: