[SOLVED] How much margin should I have on my PSU?

L0N3STARR

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Feb 20, 2020
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Hi all! I have an EVGA SuperNOVA 750 B2 PSU. I'm looking at making a GPU upgrade. How much margin should I have on my PSU?

Here is my rig:
CPU: Intel Core i7-4790K (and the fan that comes with it)
GPU: MSI Nvidia GTX 970 Gaming
SSD: Crucial MX200 250GB
HDD: Seagate Barracuda 7200.14 3TB
RAM: Patriot Viper III, PV316G186C0K, 2x8GB
MBD: MSI Z97 Gaming 5
PSU: EVGA SuperNOVA 750 B2
OS: Windows 10 Pro (x64)
CASE: Apevia Cruiser3 Green (has like 5 fans [1 x 200mm UV Green LED Side Fan, 1 x 120mm Fan - Front, 2 x 120mm Fan - Top, 1 x 120mm Fan - Rear], and some gauges)

Extras connected and being powered by PCI-e or USB:
Elgato HD60 Pro
USB 3.0 PCI-e card (4 lane)
Oculus Rift S
Mouse
Keyboard
Headset
Logitech C922 Webcam (streaming)
LED Ring Light
Steam Controller Dongle Thing

I haven't, thus far, done any overclocking, though I'd like to have the option.

What can I afford to upgrade my GPU to without experiencing PSU issues?
 
Solution
Your PSU is solid... it will be able to handle even a power hungry card like a RTX 2080ti or a Vega 64.

With either one of those two mentioned it'll be drawing around 500-550W at the absolute limit... still plenty of headroom with your PSU.
Your PSU is solid... it will be able to handle even a power hungry card like a RTX 2080ti or a Vega 64.

With either one of those two mentioned it'll be drawing around 500-550W at the absolute limit... still plenty of headroom with your PSU.
 
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L0N3STARR

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Feb 20, 2020
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Your PSU is solid... it will be able to handle even a power hungry card like a RTX 2080ti or a Vega 64.

With either one of those two mentioned it'll be drawing around 500-550W at the absolute limit... still plenty of headroom with your PSU.

Thanks! Even with all of my peripherals, I assume they're probably each < 5W. Is that correct?
 
Thanks! Even with all of my peripherals, I assume they're probably each < 5W. Is that correct?

Yes... considering your mouse and keyboard are on USB 2.0, they won't be able to draw more than 2.5W each(USB 2.0 spec is 500mA@5V). As for the USB 3.0 devices they can draw up to 4.5W max each(USB 3.0 spec is 900mA@5V).

Basically insignificant in the grand scheme of things.
 

DSzymborski

Curmudgeon Pursuivant
Moderator
Thanks! Even with all of my peripherals, I assume they're probably each < 5W. Is that correct?

Yeah, unless you're trying to power 20 hard drives or something, things that aren't the CPU and GPU are essentially rounding error. Your PSU is more than capable (and the B2 was more consistently manufactured than the B3) of running any single-GPU solution.