What does the third number mean in the new power phase nomenclature?

[KittenFish31]

I've been reading the new specs on new AMD motherboards and seems like they've added a third number in the power stage nomenclature, but after digging on the web for 3 days I haven't found any reliable info about it.

 

I know that in the 16 + 2 nomenclature, the first one is the power phase for CPU and the second is for RAM.

But now, with 16 + 2 + 2, idk what is the third number for.

 

Can you help me guys? Thank you.

 

[mariushm]

ram has its own power delivery circuit, usually near the 24 pin atx connector

 

See https://en.wikichip.org/wiki/amd/packages/socket_am5#Pin_Description

 

VDDCR	Core power supply
VDDCR_SENSE	Differential (with VSS_SENSE_A) feedback for VDDCR regulator
VDDCR_SOC	Power supply for integrated Northbridge
VDDCR_SOC_SENSE	Differential (with VSS_SENSE_A) feedback for VDDCR_SOC regulator
VDDIO_AUDIO
VDDIO_MEM_S3
VDDIO_MEM_S3_SENSE
VDD_18	1.8 V supply voltage for analog circuits
VDD_18_S5	Always on 1.8 V supply voltage for analog circuits
VDD_33	3.3 V supply voltage
VDD_33_S5	Always on 3.3 V supply voltage
VDD_MISC	Power supply for DisplayPort and PCIe PHY logic
VDD_MISC_SENSE	Differential feedback for VDD_MISC regulator
VDD_MISC_S5	Power supply for USB physical layer
VDD_MISC_S5_SENSE	Differential (with VSS_SENSE_B) feedback for VDD_MISC_S5 regulator

[KittenFish31]

10 minutes ago, mariushm said:

ram has its own power delivery circuit, usually near the 24 pin atx connector

 

See https://en.wikichip.org/wiki/amd/packages/socket_am5#Pin_Description

 

VDDCR	Core power supply
VDDCR_SENSE	Differential (with VSS_SENSE_A) feedback for VDDCR regulator
VDDCR_SOC	Power supply for integrated Northbridge
VDDCR_SOC_SENSE	Differential (with VSS_SENSE_A) feedback for VDDCR_SOC regulator
VDDIO_AUDIO
VDDIO_MEM_S3
VDDIO_MEM_S3_SENSE
VDD_18	1.8 V supply voltage for analog circuits
VDD_18_S5	Always on 1.8 V supply voltage for analog circuits
VDD_33	3.3 V supply voltage
VDD_33_S5	Always on 3.3 V supply voltage
VDD_MISC	Power supply for DisplayPort and PCIe PHY logic
VDD_MISC_SENSE	Differential feedback for VDD_MISC regulator
VDD_MISC_S5	Power supply for USB physical layer
VDD_MISC_S5_SENSE	Differential (with VSS_SENSE_B) feedback for VDD_MISC_S5 regulator

 

Now i'm a little bit more confuse.

 

So you are saying that the third number is now used for RAM power stage?
So what happends with the second number? Is it for the integrated components or iGPU within the CPU (Since is Northbridge related and northbridge is inside the CPU)?

 

Thanks for the answer.

[mariushm]

There's the cpu core , there's  northbridge / system on chip part (integrated graphics, sata controllers, some usb, extra management cores, MAYBE something for memory controller of the CPU - I didn't bother researching the latest generation so I'm not confident) , and there's misc power for pci-e lanes and displayport as the table says.

 

There's a RAM vrm that converts 5v or 3.3v to some voltage (1.2v... 1.35v), and then each ddr5 ram stick has its own dc-dc converter to convert it to what voltage the ram sticks actually need.

[RONOTHAN##]

1 minute ago, KittenFish31 said:

So you are saying that the third number is now used for RAM power stage?

No, it's the VDD_MISC rail. This powers a couple of the supporting voltages like VDDG. 

 

31 minutes ago, KittenFish31 said:

I know that in the 16 + 2 nomenclature, the first one is the power phase for CPU and the second is for RAM.

This was never the case, the second number never referred to RAM (OK, not never, there's a handful of primarily ASRock boards that did that, though they always listed that it was the memory phase). The exact thing it referred to depended on the platform, though it's usually something like SOC voltage on AMD platforms or VCCSA on Intel platforms. If you go digging for long enough you can find boards with 4 advertised values, VCore+VCCSA+VCCIO+iGPU. 

 

On AM5 they are VCore+SOC+VDD_MISC. 

[KittenFish31]

15 minutes ago, RONOTHAN## said:

No, it's the VDD_MISC rail. This powers a couple of the supporting voltages like VDDG. 

 

This was never the case, the second number never referred to RAM (OK, not never, there's a handful of primarily ASRock boards that did that, though they always listed that it was the memory phase). The exact thing it referred to depended on the platform, though it's usually something like SOC voltage on AMD platforms or VCCSA on Intel platforms. If you go digging for long enough you can find boards with 4 advertised values, VCore+VCCSA+VCCIO+iGPU. 

 

On AM5 they are VCore+SOC+VDD_MISC. 

Thank you this makes it more clear.

So VDDG is related to infinity fabric I/O chip on the CPU, right?
 

VCore for CPU overclocking, SOC for RAM overclocking and VDDG for infinity fabric I/O Die (?

[RONOTHAN##]

31 minutes ago, KittenFish31 said:

Thank you this makes it more clear.

So VDDG is related to infinity fabric I/O chip on the CPU, right?
 

VCore for CPU overclocking, SOC for RAM overclocking and VDDG for infinity fabric I/O Die (?

Yes. VDD_MISC does power more than just VDDG, that was just the first one I thought of. In practice as long as that voltage is above the others, it doesn't really matter.