ASRock Z97 Extreme9 - Power loss on high load

Your PC's hardware listing is incomplete to be able to diagnose your problem, although I have an idea about what is happening that I will describe below.

What kind of PC case are you using? How many and what size fans are you using in the PC case, and how do you control their speed?

What type of CPU cooler are you using? Have you ever watched the CPU temperature while you are gaming?

You have two video cards that vent most of their heat into the PC case. Unless that heat is removed quickly from the PC case, the heated air is used to try to cool the CPU with your unknown CPU cooler. So you could easily have a CPU over heating problem if you are using the stock Intel CPU cooler.

Your Enermax Platimax PSU  has a specification of 1350W. Let's look at the output on its multiple rail 12V design:



We can see the PSU has four +12V rails rated at 30 Amps each, and two +12V rails rated at 20 Amps each. The total +12V output capacity is 1350W, which is 112.5 Amps x 12V = 1350 Watts.

The potential problem I see here is the Amp rating of each of the six +12V rails.

Four rails at 30 Amps each is 120 Amps total, over the 1350W/112.5Amp rating.

Add to the 120 Amps, the two rails at 20 Amps each (40 total), for a total of 160 Amps.  160 Amps x 12V = 1920 Watts.

My point here is the individual power rating of each of the six +12V rails cannot be maintained if all of them were in use at their full capacity.

Even if you did not use the two 20 Amp +12V rails, the four 30 Amp rails would be beyond the maximum capacity of the PSU. This does not even include the the +5V and +3.3V load on the PSU, which will further reduce the total power available.

If you were using 20Amps from each of the six 12V rails, that is still 1440W/120Amps, again over the 1350W maximum rating of the PSU.

As you said you already tried to "oversplit", or distribute the power needed for each video card across as many of the +12V rails as possible. Each video card requires two eight pin power connectors, for a total of four. Do you have one eight pin cable connected to each of the four 30Amp +12V outputs? That would be the best way to supply power to your two video cards.

In reality, it is probably not that the PSU cannot supply enough power, but it is the power limits on each of the +12V rails that may be causing the PSU to shut off power to the video cards.

I don't know the true amount of power the video cards are using, but I wanted to explain to you how it is possible for a PSU design like yours to fail IF it is not connected correctly to the video cards, etc, in a PC.

If the power usage on one of the +12V rails goes beyond the 20A or 30A rating, it will shut off.

Your mother board has an extra power connector at the bottom of the board to supply extra 12V power to the PCIe x16 slots. Do you have a cable connected to that connector?

Your board has two, eight pin CPU power connectors at the top of the board. Unless your CPU is highly over clocked, you do not need to connect cables to both of those connectors, one eight pin connector/cable will be enough.

A mother board will turn off the PC if the CPU over heats, or if the PSU shuts off power to one or more components in the PC, like a video card or the CPU.

I'll let others comment about your problem, but I would like to you to answer the questions I asked at the beginning of this post.

So many things.

Edited by CosmiChaos - 07 Jan 2016 at 2:00pm

Edited by CosmiChaos - 08 Jan 2016 at 12:04am

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