Quote Originally Posted by largon View Post
I just tried it on my PX3544-chipped G92GTS but I can't seem to find a i2c bus (0-99) that doesn't slap me with "invalid".
Please read my previous comment about I2C bus indices, altering I2C bus indices is not a correct way. You should try to probe difference i2c device addresses instead. Each I2C device address is defined by developers (e.g. ADT7473 fan controller use fixed address 2E, VT11xx VRMs use fixed register 70 by default, but it can be strapped to 7x AFAIR, etc).
You must have Primarion PX3544 datasheet to know where it normally resides. I've peeked inside reference 9800 GTX BIOS to see if it is initializing any I2C devices and it does seem to write something to I2C device 6A (writes single byte 86 to register 80 of this device). It can be Primarion PX3544, but I've no strict info about it because I don't have any info on this VRM I2C interface.