Similarly, does AMD have international warranty?
I wrote to AMD about this. Received a call from one of their offices in India the very next day. They said that the serial number isn't necessary on the invoice and even told me that they have international warranty. So even if you purchase from US you will get warranty in India.
Also, does AMD cpu warranty transfer? AMD Warranty is only good to the original purchaser and is not transferable. Without an Official Receipt showing the Original Owner and date of purchase from the Retailer you won't be able to open an AMD Warranty unless AMD ask for some other proof that you are the Original Purchaser.
Keeping this in consideration, do Ryzen CPUs have a warranty?
AMD warrants that processors sold through the AMD Processor in a Box Program, which have a "qualifying" serial number, when properly installed and used, will be free from defects in material and workmanship and will substantially conform to AMD's publicly available specifications for a period of three (3) years after
Is Ryzen good for long term?
In the long term, this is great for consumers. Not only are CPUs getting faster and more cores, the price for these CPUs is coming down. Competition is something every market needs and Intel had no competition from AMD before Ryzen.