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Description of problem:
Get kernel panic when attempting to install EL9.0 on a machine with an Intel Core 2 Duo CPU.

Version-Release number of selected component (if applicable):
Kernel in initial 9.0 release

How reproducible:
Always.

Steps to Reproduce:
1. Try to intstall on Core 2 (Duo) machine

Actual results:
Kernel panic a few seconds after starting boot of install process.

Expected results:
No kernel panic.

Additional info:
RH announced that RHEL9 does not support 'old CPUs', and the cutoff point appears to be somewhere between Core 2 (Duo) and Core i5.

Core 2 (Duo) is more than adequate to run common workloads efficiently for many more years ('many' as in 1,2,3,many).  Aided by inexpensive upgrades such as SSD and RAM.

We have researched Core 2 (Duo) and found that it was a significant jump in capability from what preceded it.

Evidence indicates there's a lot of Core 2 Duo machines still in use, and many workloads will benefit from the software versions provided by RHEL9 (compared with earlier RHEL versions).

Thus RH can potentially avoid significant e-waste by moving the RHEL9 CPU cutoff point such that Core 2 (Duo) is supported.

(In reply to fedora-info from comment #0)
> Thus RH can potentially avoid significant e-waste by moving the RHEL9 CPU
> cutoff point such that Core 2 (Duo) is supported.

Waste was indeed a concern, but an additional concern was the power efficiency of these older systems.

Red Hat worked with the industry to define specific ISA support levels and used x86-64-v2 as the baseline for RHEL 9 and CentOS 9.

Modern systems can be significantly more power efficient, and old systems can be recycled.

Florian Weimer discusses some of details in this blog post in 2021:
https://developers.redhat.com/blog/2021/01/05/building-red-hat-enterprise-linux-9-for-the-x86-64-v2-microarchitecture-level

The use of x86-64-v2 does deprecate some older x86_64 hardware.