Bitcoin Forum

Hello,

I like to ask how many riser can you safely add per VGA port in the PSU? i would like to put all riser connection to the first PSU but there is not enough vga 6 pins to go, I would be using 6 pin adapters to daisy chain multiple risers in one VGA port, not sure if this is safe or not.

Thank you!

Not more than 2-3  max or you will start facing electrical issues.

It depends on the power supply.

Most can handle 2 no issue, many can handle 3 - any power supply that comes with "8-pin + 6-pin" VGA power cables are fine to run 3 risers on one port.

4 - there are a FEW that can handle 4 risers from one "VGA" port, but I don't recommend trying it unless the PS in question comes with at least one "8-pin + 8-pin" cable for VGA power.

Thank you @ironkid and @QuintLeo

I will keep at most 3 on one vga port, do you still follow to put all risers on should be on the first psu? its a bit hard to put all riser on the first psu.

One VGA connection from PSU can handle 150w, so max 3 risers. Do NOT put riser and gpu on different power supplies.

The riser can eat more than 75 watts PER RISER - PCI-E bus spec allows 75 watt draw AND the riser chews through a little additional power in it's voltage conversion circuitry.

VGA connection at the power supply VARIES - do NOT assume 150 watts, some only put a single 6-pin connector on a PS port and likely are only RATED 75-100 watts ballpark for the PORT.

Technically you shouldn't, but I noticed a few months ago I have about 5 rigs that have some risers powered on different PSU's than the GPU.

I didn't feel like changing it.

4 months later. Still going. Zero issues.

Check what the cable is rated at by checking the cable it's self, your PSU box, or the PSU booklet or website. I'm sure it varies with PSUs. This is why it's highly suggested you never mix modular cables from different PSUs.

It can draw 75w, but does it? If both 6 and 8 pin cables are connected to GPU.

 The PINOUT on modular cables from different PSUs is often not the same - even the "same Manufacturer" often has different cables on different models, as those different models are often not actually MADE by the same manufacturer.

 THAT is why you don't mix-and-match without doing careful research first.


 Draw from the PCI-E bus varies widely depending on the specific card.
 There have been tests that showed peak draw on some cards EXCEEDING the PCI-E spec by 5-10 watts - yes, that's with all of the PCI-E POWER connectors attached to the card at the time.
 The AMD RX 470/480 cards were NOTORIOUS this way, 'till AMD released a new driver version that apparently adjusted the "power split" the cards used to pull less from the bus.
 Some of the affected models were 150 watt or so TDP but had an *8 pin* PCI-E power connector.