Vcore is the Voltage for the CPU core, Vio is the Voltage for the Chipset, RAM and AGP slot.
As fast as you can get it while staying within amd's vcore specifecation with the temperature under control. It's not high clock speed that will kill or reduce the life of the chip, it's higher vcore, because it causes electromigration in the chip, and higher heat which cased by the higher vcore and clock speeds.
The external voltage of a processor is commonly referred to as the "core voltage" or "Vcore." This voltage is essential for powering the processor's internal components and ensuring proper operation. It can vary depending on the processor's architecture and design, and it is typically regulated by the motherboard's voltage regulator module (VRM).