I would understand it. I’ve heard him say that the EPS12v connections supply only CPU power which I know to be incorrect on at least some contemporary motherboards.
Length of the wire is not a good argument to make. If you look at the straight-line distance from the top of the board eps12v lines to the leftmost part of the PCIe slots, and from the ATX 24 pin 12v lines, the length is about the same, if not longer from the ATX24 side. The Vregs come down the left hand side of the board on many boards, certainly AM4, almost to the first PCIE slot. So we’re talking about an actually very tiny amount of copper.
The boards for sure do need at least 1 of the 2 12v lines. It seems like the management bus and stuff like that are isolated 12v setups from the rest of the system, so you’ll need the lines to post… butt…
This is only true in desktops, not servers. Servers for sure mix their EPS CPU and PCIe rails too, though some don’t. And have extra EPS12v connectors.
Yep, this is the case. BEEEEEEEEEP. For this particular board anyway.
The 1060/1070 also draws kind of a lot of power from the slot. I have some PCIe storage devices that also use a lot of power. There is a bit of a negotiation process to move from 35w (25w in old days) to 75w iirc anyway.
I believe this was the original spec, and the the combined limit is still 75w but the limit for 12v alone was bumped to 6.5a from 5.5a. Oh, and the GT 7300 was the first card to take advantage of this bump IIRC, it was a card using ~70w on the 12v rail. These cards mostly do their own regulation except for a very little bit of 3.3v logic to handshake to get into high power mode.
But yes, those are within the numbers I already quoted.
12v fan headers, memory, etc. The RGB LEDs and usb use 5v, some glue logic stuff is 3.3v but almost everything else is using the 12v rail and stepping down to low voltage at lots of current. The chipset is almost certainly using the 12v rail, maybe not, but it’s the same lithography process as the iodie, and that probably wants around 1v operating voltage.
I do not believe that just two 12 pin lines would be sufficient for two high current devices on the motherboard, plus fans pumps, chipsets, etc.
10a for cards, 3a for fans and various other 12v bits, memory, chipset, other 25/35w addin cards etc fit in the last 3a? No. The taichi is a 3x16 slot motherboard, so it has to draw from somewhere.
Besides, if your power stage design is such that you have a multi-rail power supply and the board designer assumes each 12v input is a different rail then droop on one rail is more easily compensated from another rail. SSI spec talks about that a bit…
This is incorrect, solid ones are the 96w ones. They are prettymuch the standard now, but not always. I do see them mixed on cost down boards. The original spec was 7a = 336w for the 8-pin connector, which is around the number buildzoid usually quotes as the “safe” number IIRc.
Several things I said are in the reference spec:
8a per pin, etc, whichj I think we agree on.
Not all cases the CPU power is mixed, but in this case it seems to be. I generally assume that is true when I see two+ PCIe x16 slots plus a lot of 12v “gravy” like a bunch of high-current fan headers for pumps and whatever.