[SOLVED] Exaggeration in Power Supply Requirement

simptive

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I switched from RTX 2060 to RX 6700 XT.
I had 550w Gigabyte PSU which I found really cool. After reading PSU requirements from vendor websites and answers from different forums, I decided to buy a 850 watt PSU for future safety - influenced by the common belief on internet.

However, after installation, I put a wall wattage meter in between power source and my whole setup including Display. (i can't doubt my wattage meter).

What I found after 6 hours of intensive gaming, benchmarking using various tools and cpu/gpu burning was annoying. The max wattage my setup consumed was 360 watt!

I tried same on my 550w PSU. Result was same. So, my question is, why people think like we're living 20 years back when GPUs and PSUs weren't efficient and had multi rails of limited power?

What I should make sure is a good quality PSU which shouldn't exceed 90% of its limit.

Please mention your setups and max wattage it consumes if you have any wattage meter.

My Setup:
Ryzen 5 3600 (Default core boost)
RX 6700 xt (no over clocking)
DDR4 3200Mhz 8GBx2
850w PSU
Lots of fans and RGB
SATA SSD and HDD
144hz Monitor
Gaming mouse and Keyboard
 
Last edited:

Eximo

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Yep, you need a decent oscilloscope to catch transient spikes. ATX 3.0 spec has some new requirements, but they appear to be sub-par for the current GPUs. 200% load for 100 micro seconds. Testing shows some of these transients on current GPUs can last as much as 300 micro seconds.

Rest of the system indeed. 350W GPU, 150W CPU, at 500W already before accounting for motherboard, fans, pumps, lighting, drives, and USB devices. 850W PSU covers most high end builds with a little room for capacitor aging.

Partpicker puts my build at 560W, or 65% of 850W. That puts it right in the middle of the 50-80% range for maximum efficiency. Now obviously that is full load of the CPU and GPU which isn't terribly likely under most circumstances. But there is also the matter of overclocking. I have removed the power limits of the CPU, but not yet bothered to overclock the GPU. And it really does pull 350W at stock, not sure I want to give it any more.

360W out of 550W is also right in the efficiency range at again 65%. So it is the right size, but the quality comes into question.
 
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punkncat

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It isn't unreasonable to consider that GPU manufacturers build in quite a bit of variance when making PSU requirement recommendations simply based upon the nearly endless variety of components the graphics card could be used with. In this case it would be safer to err on the side of caution and recommend something larger than you could need in order to keep consumers from returning cards they didn't have enough power for as bad.

With that said, there are also a lot of GPU and CPU on the market that are capable of pulling WELL more than the reference amount of power.
 
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Lafong

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However, after installation, I put a wall wattage meter in between power source and my whole setup including Display. (i can't doubt my wattage meter).

What I found after 6 hours of intensive gaming, benchmarking using various tools and cpu/gpu burning was annoying. The max wattage my setup consumed was 360 watt!
It is surprising that you so rarely hear of people using a wattage meter on this site. Pretty cheap and handy device to measure power consumption on most anything in your house. Probably a threat to the sales of 850 watt power supplies.
 
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https://www.techpowerup.com/gpu-specs/radeon-rx-6700-xt.c3695
This says 550 watts
Suggested PSU: 550 W

https://www.techpowerup.com/review/amd-radeon-rx-6700-xt/35.html

Max around 230 watts but can spike to 320 W for a really really short time. So 550 W should be enough.

It's not all about wattage either. Wasn't the PSU from Gigabyte that blew up randomly also a 850 W? Yeah... https://www.tomshardware.com/news/gigabyte-releases-statement-on-exploding-psus
Would you like to have a 550 W version of that? I wouldn't.
 
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DSzymborski

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Gigabyte P550B

Gigabyte UD850GM

I found both really reliable as power switch to UPS and jerks at the main is very common at my home. They never give me feeling of weakness.
Given that you didn't have any issues witih a cheaply made group-regulated PSU that fails basic transient response tests on the +3.3V rail and had some of the worst ripple measurements of a PSU released by a major company today, I'd suggest that your "feelings of weakness" diagnostic is a very poorly calibrated one.

This is the opposite of "really cool" both figuratively as having junk PSUs in your PC is hardly the latest fashion trend and literally as the PSU is so cheap that it doesn't even have OTP protections and gets very hot.

 

KyaraM

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Also all modern GPUs has a transient power of 3x the AVG power consumption, for example 3090 with a AVG power of 350W has a transient power of almost 700W, the psu must handle that spike. Check Gamer Nexus, youtube video about transient power.
700W is 2x the average of 350W, not 3x. 3x would be 1050W. Also, for my card, the 3070ti, I found a measurement of 407W for transient vs 290W regular, so it seems to differ between models and surely also cards of the same model. That's "only" a 50% plus over regular draw. So I'm not sure it's universally applicable. Also, undervolting might positively affect transients, too.
 
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If you want a high quality PSU they either don't make that many rated for low wattage or when they do they aren't really that much cheaper to buy than the higher power versions. The other thing to consider is if you are buying a high quality PSU that will last 7 to 10 years or more you never know when gaming PC power requirement will suddenly jump up at notch(Ada Lovelace anyone?)
 
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simptive

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Given that you didn't have any issues witih a cheaply made group-regulated PSU that fails basic transient response tests on the +3.3V rail and had some of the worst ripple measurements of a PSU released by a major company today, I'd suggest that your "feelings of weakness" diagnostic is a very poorly calibrated one.

This is the opposite of "really cool" both figuratively as having junk PSUs in your PC is hardly the latest fashion trend and literally as the PSU is so cheap that it doesn't even have OTP protections and gets very hot.

Are you referring to P550B or both?
 

simptive

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Gigabyte is the only PSU brand available in your region?
Nope but for the price range it seemed best option. Three fearures in best price:
  1. Gold+
  2. Modular
  3. Flat cables
BTW I didn't know about its psu blast saga. I hope UD850GM won't have that fault. I got it in around 100 usd in my country.
 
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Zerk2012

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The thing with watt metters is they don't react fast enough to show very fast watt spikes.

But most manufacturers sites over state the watts needed for the cards because they have no clue what the rest of your PC parts are or if you are going to buy a cheap overrated PSU.
 
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Eximo

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Yep, you need a decent oscilloscope to catch transient spikes. ATX 3.0 spec has some new requirements, but they appear to be sub-par for the current GPUs. 200% load for 100 micro seconds. Testing shows some of these transients on current GPUs can last as much as 300 micro seconds.

Rest of the system indeed. 350W GPU, 150W CPU, at 500W already before accounting for motherboard, fans, pumps, lighting, drives, and USB devices. 850W PSU covers most high end builds with a little room for capacitor aging.

Partpicker puts my build at 560W, or 65% of 850W. That puts it right in the middle of the 50-80% range for maximum efficiency. Now obviously that is full load of the CPU and GPU which isn't terribly likely under most circumstances. But there is also the matter of overclocking. I have removed the power limits of the CPU, but not yet bothered to overclock the GPU. And it really does pull 350W at stock, not sure I want to give it any more.

360W out of 550W is also right in the efficiency range at again 65%. So it is the right size, but the quality comes into question.
 
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