No. There is no official GM Bank in Yamaha synthesizer's (that's why they don't have the official GM logo) there are simply MOXF Voices mapped to respond to the GM Program Change list. Unlike other synths that have a separate chipset for GM grade sounds, the sounds found in the MOXF's pseudo-GM bank simply follow the program change numbers but feature the same advanced architecture and access to effects as the other MOXF Voices. There is no downgrade in sound quality in the sounds in this bank.