Its GDDR6
Not DDR1
Clock in DDR memory is complicated…

Depends.

Microsoft uses saphire rapids (cpu that got smoked in reviews) couse it has better single core performance for their AI servers. You will find a case for CPU.

For PC depends on your workload. If you are doing normal stuff + gaming just buy this or last gen i5/r5. No need to waste money.
You will have more single and multi thread performance than you need.