PSU Dual Rail Amperage Question

[halomrfrags]

So I have a friend who is getting an MSI GTX 970 4 GB Twin Frozr, and he is worried about the amps on his power supply not fully powering the card.

Setup he currently has:

AMD Ryzen 3 1300x @ stock speeds
EVGA GeForce GTX 960 4GB ACX 2.0
1 TB 7200 RPM Toshiba Hard Drive
DVD Reader
1x8 GB 2666 MHz DDR4 Ram (Not sure exactly on the ram speed, somewhere from 2666 to 2888)
ASRock-A320M-DGS
Rosewill RD500-2DB 500W Power Supply
2 Case Fans

He plans on upgrading the CPU to a Ryzen 7 1700 (Non X version) along with the GTX 970 previously mentioned.

He is worried on the GPU not having enough amperage on dual rails, and wants to know if he will have enough power to power it all. He would also like to know how to calculate the amperage on the 12V Rails with dual rails. We would also like to know the max amperage of the GTX 970 mentioned.

One rail has 15 Amps, and the other has 16 Amps.

Pic of power supply specs:

Thanks.

 

[RememberThe5th]

Thats around or less 180W per pcie and cpu. Which connectors does he have for cpu and gpu?

I think that load is splicing between rails and all rails are on same 12V.

I recommend new psu.

 

[Rexper]

Maximum 12V rail output capacity could range between 16A (192W) and 31A (372W). There's no way to calculate from those specs.

I couldn't find anything about the power distribution of the two 12V rails. Usually it's the EPS connector (maybe a PCIe connector aswell) on one rail, everything else on another. Or maybe the manufacturer lied about multiple 12V rails, where it's really a single 12V rail without OCP.

According to this review, the GTX 970 whilst gaming consumes 11A from the PCIe cables, and ~3.6A from the Motherboards PCIe slot (12V). During the "stress test", it consumes an average of 16A from the PCIe cables, and 4A from the motherboard.
Looking at max consumption (from the graphs), it's about 20A from the PCIe cables, 5.5A from the motherbaord.

If both PCIe cables are from a single rail, you could run into problems.

The 8pin PCIe connector is rated for 150w.
If the 8pin PCIe and motherboard are on the same rail, you can run into issues
During gaming and torture, the r7 1700 consumes 3.6A and 6.83A from the 12V, respectively.

So even if there is a PCIe cable + EPS cable on a single rail, you could run into issues.

Unless of course the dual 12V rail is a lie, and there isn't OCP (current caps on the rails), in which case further supports the PSU is low quality.

Given it's relatively load 12V output, Solytech OEM, 1 year warranty, and lack of information on the 12V rails, it's probably a crap power supply.
I'd replace it with a good power supply, such as the Corsair CXM / CX (grey label) or be Quiet Pure Power 10.