Topic: How much is the power draw for a SATA connected riser? (Read 206 times)

Every single one of my rigs (6x 570 or 580 each) uses the SATA power connector to power the risers. Each card also has the 8 pin connector. I only have 3 cards per SATA power cable.

Don't forget that the voltage conversion circuitry on the riser itself will eat a few watts.

 If you can't keep the card under 50 watts and PREFERABLY under 45 watts *RELIABLY*, don't run it on a SATA powered riser unless you are willing to run the risk of the SATA power connector failing, melting, or even burning at some point.


 Don't even THINK about powering multiple risers with a single SATA "chain" - I've NEVER seen a chain that was rated to handle more than about 100 watts at 12VDC, and most have wires that are only rated to handle 5 amps (60 watts) for the chain.
 The presumption seems to be that most SATA chains will have at most a SINGLE DVD/CD-ROM/Blueray type drive (1.5-2.5 amps normally on SATA powered versions) and the rest of the devices will be hard drives/SSDs (normally less than 1 amp each) drawing +12VDC power.

 2 risers from a single MOLEX chain can also be an issue - CHECK THE WIRING, in many cases it's only rated to handle 7 amps of 12 VDC though it's more LIKELY than a SATA string to be designed for 10 amps or more as many older CD-ROM and DVD-ROM drives with a MOLEX power connector would draw 2.5-3 amps per drive and a lot of FANS draw over 3 amps, so most MOLEX chains tend to have heavier wiring than SATA chains.

 As far as why the card doesn't get all it's power from the PCI-E power connector - in many cases it CAN'T do so because it's rated to draw more power even at FACTORY stock settings than the connector(s) on it are rated by PCI-E to supply.
 Then there are cards that don't have a PCI-E power connector at all (most 1050 and 1050 ti models for example) and MUST draw all of their power from the PCI-E bus connection.

Depends on the card.  For example, if the GPU's peak is 150W and it uses only one 8-pin PCIe input, then chances are it won't draw all 150 watts from a single connector (that's 100% utilization).

only if power consumption from riser is very low like 25-30W (some old cards)
I recommend 2 max. for actual cards.
It is good to measure the riser consumption with the DC clamp meter (yellow wire)

That's for each connector, right?

Can you power 3-4 risers with one SATA cable?

for SATA power is maximum 54W - 3pins/1,5A/12V

Why wouldn't the card get all its power from the 6/8 pin connector? Wouldn't that be simpler?

One more question, as I am no riser expert.

Is it acceptable to power two risers with one peripheral cable that splits into molex?  So the periph cable directly into the 4 pin power for two risers

I measured this before with a current probe. Basically it uses like 50 Watts with the RX 470.

Doesn't matter whether you dual mine or not. The 50 Watts is mostly powering the memory.

The cards would be powered from the PSU, not via the risers themselves

SATA does 55W, an a PCI-E slot needs 75W, so you run the risk of burning out a riser or possibly causing a fire.

Now if you can get a card to below 55W, you may be fine. YMMV

Use the 4-pin molex or a PCI-E 6pin power riser

Sorry I should have been more clear.  Power draw from the riser power connector

Thanks! 

power draw on a powered riser or on a unpowered riser ?
Power draw from the pcie slot where the riser plugged in ,or power draw from the riser power connector ( sata/molex/6pinpcie ) ?

Since the PCIE connection is rated for 75W, I assume each GPU may potentially draw up to that much.

Having trouble finding a good estimate for the power draw on a riser.

Thanks!