System is a Dell with a 64-bit 3 GHz Intel Q9650 Core 2 Quad CPU.
It runs Windows 7 Professional (x64) SP1 and shows all 4 cores in Task Manager's Performance tab. Most of the installed Windows programs are 64-bit versions.
Ubuntu 18.04 LTS refuses to install, saying this is is an "i386" processor.
It will not even allow the option to "Try Ubuntu"
This system supports multiple 5 TB drives as a NAS. Also, 16 GB RAM.
64-bit hardware was introduced by Intel in order to support larger amounts of both.
It was never intended to cause people to get stopped as operating systems began to require more-specialized CPU architectures like AMD's "AMD64"
Who is driving this bus? (pardon the pun)
Why aren't all 64 bit processors supported by this 64-bit operating system?
This doesn't make sense.
Your Intel Q9650 64-bit Core 2 Quad CPU is not supported by Windows 10 either. It was released in 2008 and considered too old for modern operating systems.
Looking at your specs on Intel's Website I noticed it doesn't have hyper-threading. Also it doesn't have Turbo-Boost which is probably less of a concern.
More importantly there is the 64-bit instruction set which has evolved over time. Linux tests each CPU during boot to see if certain instructions are supported. I can't find the reference I was looking for but this one outlines the kernel checks:
After we have set up the stack, next step is CPU verification. As we are going to execute transition to the long mode, we need to check that the CPU supports long mode and SSE. We will do it by the call of the
verify_cpu
function:This function defined in the
arch/x86/kernel/verify_cpu.S
assembly file and just contains a couple of calls to the cpuid instruction. This instruction is used for getting information about the processor. In our case, it checks long mode and SSE support and returns0
on success or1
on fail in theeax
register.If the value of the
eax
is not zero, we jump to theno_longmode
label which just stops the CPU by the call of thehlt
instruction while no hardware interrupt will not happen:If the value of the
eax
register is zero, everything is ok and we are able to continue.To summarize there are many things your decade-old CPU doesn't support that modern 64-bit processors support.
Please download 19.10 version (AMD64) and while installing,when you see a keyboard and a human icon on bottom center of your screen,press CTRL + ALT and run Install ubuntu with safe graphics. It will work for Q9650 G41 motherboard,as i have the same specs. I hope this will work for you.