Did I get this right?

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exkhill

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So I have to be sure that I understand how to know if a PSU can power a GPU.

Obviously a quality one will be better than a cheap one.
Moving on, one 6 pin can supply 75w and a PCIe slot additional 75w. So theoretically every GPU that has only one 6pin (which can then draw up to 150w?) the PSU can run it no matter what the CPU's TDP is?

I also noticed that on a PSU sticker it says +12V max load = 324w. So anything within those 324w would be a safe zone? So theoretically a 150w PSU and a 150w CPU could be good, or it would cause an overload on the PSU and it could overheat?

And there are amps, 30A is the lowest border you should go at a gaming PC, as I heard.

Is there anything I'm missing?
(Sorry if this question doesn't fit the format of this forum)
 
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Eximo


That is terrible advice. Even if they have safe shut downs, you don't want your computer to be constantly shutting itself off when you want to use it.

And in practice that is not always true. Power fluctuations can cause unexpected behavior that can cause damage.

An overloaded power supply can indeed catch fire and even explode, ideally OCP or OTP will prevent that from happening, but the only way to test those things is to the point of failure, something that you can't do to a consumer product. Samples are tested, any computer component...
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Eximo

Eximo

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Power = Current * Voltage
Watts = Amps * Volts

324W @ 12V = 27 Amps

The total system wattage must be lower then the total output of the supply. You need to take into account the motherboard, fans, memory, drives, etc. This means the CPU TDP, which exclusively runs on 12V these days, is very important to the estimate.

75W through the PCIe slot is a standardized limit, same with the PCIe 6-pin connector. In reality they can handle a little more, but they are not the supply, only the carrier. The limits are to prevent wires from overheating (thus increasing resistance, and voltage drop)

It is safe to say that any GPU with a single 6-pin PCIe connector has a maximum TDP of 150W though, generally they will be less. If it is borderline, they will add another 6-pin or switch to a single 8-pin.
 
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Eximo

Eximo

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That is terrible advice. Even if they have safe shut downs, you don't want your computer to be constantly shutting itself off when you want to use it.

And in practice that is not always true. Power fluctuations can cause unexpected behavior that can cause damage.

An overloaded power supply can indeed catch fire and even explode, ideally OCP or OTP will prevent that from happening, but the only way to test those things is to the point of failure, something that you can't do to a consumer product. Samples are tested, any computer component could have a flaw that was not evident in testing or caused in shipping/storage.

In general you want to load a power supply between 50-80% of its 12V maximum wattage. This is to maximize efficiency and prevent excessive fan noise. Which is usually slightly less then the rating for the whole supply. Your 324W 12V rail is likely to be found in a 380W or 430W power supply, unless it has multiple rails.

Older or bad power supplies are easily identified by excessive 5V wattage output that is included in the total.
 
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exkhill

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Yeah Blackbird has helped me a lot when I had questions and needed help. I will buy that guy a beer one time.
Thanks eximo for answering. Yes it is a 380w psu. I'm wondering about this because I found some older cheap AMD gpu's that I find good but not really with an ideal TDP if you know what I mean.

@Winterra calm down.
 
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