This week TechARP reveals the meaning of the PEG Port VC1/Map BIOS setting, you can learn about it over here. This setting enable you to reconfigure which specific traffic class can use the second virtual channel of the PCI Express graphics port. For the highest performance, it's recommended that you leave this setting at the default setting of TC7.
Unlike the sideband signals used to prioritize traffic on the AGP or PCI bus, PCI Express uses virtual channels and traffic classes (also called transaction classes) to decide what traffic gets a higher priority to bandwidth on the bus at any particular time.
This BIOS feature allows you to manually map a specific traffic class to the second (VC1) virtual channel of the PCI Express graphics port. This is the higher-priority virtual channel, so mapping a specific traffic class to it will increase bandwidth allocation priority for that traffic class. However, this is not a requirement.
When set to Disabled, no traffic class will be manually mapped to the VC1 virtual channel.
When set to TC1, the TC1 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC0 to be given access to a higher priority virtual channel.
When set to TC2, the TC2 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC1 to be given access to a higher priority virtual channel.
When set to TC3, the TC3 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC2 to be given access to a higher priority virtual channel.
When set to TC4, the TC4 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC3 to be given access to a higher priority virtual channel.
When set to TC5, the TC5 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC4 to be given access to a higher priority virtual channel.
When set to TC6, the TC6 traffic class will be manually mapped to the VC1 virtual channel. This allows traffic with a higher priority than TC5 to be given access to a higher priority virtual channel.
When set to TC7, the TC7 traffic class will be manually mapped to the VC1 virtual channel. This allows only traffic with the highest priority to be given access to a higher priority virtual channel.
Generally, it is recommended that you leave this BIOS feature at the default setting of TC7. This allows only the highest priority traffic to be given access to the higher priority VC1 channel.
