Question How power-hungry a GPU can a 620W PSU support ?

[strobolt]

I'm currently running MSI 5700XT OC Mech and i3-12100F with an old Corsair HX 620 W PSU. I've been thinking of getting an i5 or i7 as an upgrade which would probably take the CPU from 65 W TBW to 120 TBW and MTP increased along the same lines, depending on the final model chosen. I'm using the system in 2k gaming with 75 Hz monitor (though considering on upgradin this to 144 Hz at some point) as well as photo editing, mainly with Adobe Lightroom.

The question is that how power-hungry a GPU can this PSU support?

I'm a bit worried that stepping up from i3 will then make the 5700 XT unfeasible and would then require a PSU upgrade as well at that point. Although I have undervolted the 5700 XT down from stock 1,2 V to 1,1 V and limited the power draw to -20 % to try to limit the power draw. I am facing a bit of instability with the undervolting as while the stress tests run without issues, the applications cause errors every now and then. I'm thinking this might be an issue of transient power spikes.

 

[Aeacus]

The question is that how power-hungry a GPU can this PSU support?

PSU has 3x +12V rails;

So, 12V times 18A = 216W per rail.

I suggest retiring the old HX620 and getting new, modern, good quality PSU. E.g Seasonic Focus/PRIME or Corsair RMx/RMi/HXi/AXi. 750W PSU would be enough for your current GPU + i7.

 

[Ralston18]

Start here:

https://www.tomshardware.com/reviews/best-psus,4229.html

Read the entire review and then apply 3 or 4 of the calculators.

If any given component provides a range of wattage values then use the high end value.

Consider the GPU wattage requirements were likely determined under ideal circumstances and may therefore be somewhat understated.

Likewise consider that the PSU wattage value was likely established under ideal conditions.

Quality matters.

 

[strobolt]

PSU has 3x +12V rails;
So, 12V times 18A = 216W per rail.

I suggest retiring the old HX620 and getting new, modern, good quality PSU

I'm not familiar with how the rails work. Are these directly linked to specific connectors or does the PSU somehow balance between them. Does it really matter how many rails the PSU has? From your comment I'm getting an impression that there would be some linkage between how many watts a single rail can deliver and how much power a single component can use. E.g. max. 216 W per CPU/GPU in my case?

Start here:

https://www.tomshardware.com/reviews/best-psus,4229.html

Read the entire review and then apply 3 or 4 of the calculators.

If any given component provides a range of wattage values then use the high end value.

Thanks for the article link!

I get it that it's important to get a good quality PSU with sufficient wattage when building a system. And grabbing a 750W PSU from that list would be clearly the way to go for a new system build from scratch. Many calculations suggested 650 to 700 W for my use case.

I guess my question was more that would it be possible to get away still using the old PSU or would it make sense to at least try and then get a new PSU if I run into issues. But you seem to suggest that would be safer (risk of braking CPU/GPU?) to just get a new PSU. And I suppose that should then get me through the next 10+ years.

How important to do you see currently to get one with ATX 3.0 and the 12+4 pin connector? The article seems to suggest that it would be required for future GPUs but I'm not quite sold on that...

 

[DSzymborski]

It's not super-important to get the new connector. It's still a nice to have, but the adapters have been rapidly improving as long as they're from good sources.

There are lots of different ways they express rail configurations. That you have this reflects on just how old this PSU is. There used to be, under ATX spec, a current limit of 240 volt-amps per rail. That requirement was removed in *2007*! I strongly urge retiring quality PSUs no longer under warranty to lesser at the earliest convenience. A significant PC upgrade is one of those times where that an old PSU should be retired or moved to an easier task.

 

[Aeacus]

Are these directly linked to specific connectors or does the PSU somehow balance between them.

Directly linked. No "balance" between the rails.

HX620 is semi-modular, where 24-pin ATX and +12VEPS are connected to PSU. +12VEPS (to power the CPU) takes up one +12V rail.
PSU has two 6-pin sockets for PCI-E 6-pin cable. 2 sockets, both, use another +12V rail.
3rd +12V rail is inside 24-pin ATX cable and peripheral (MOLEX) cables.

From your comment I'm getting an impression that there would be some linkage between how many watts a single rail can deliver and how much power a single component can use. E.g. max. 216 W per CPU/GPU in my case?

Yes.

Theoretically, HX620 can deliver: 216W + 75W = 291W for GPU.
75W is via the PCI-E socket on MoBo, powered by 24-pin ATX cable.

But you seem to suggest that would be safer (risk of braking CPU/GPU?) to just get a new PSU.

Better safe than sorry.

While HX620 is good PSU, it is way too old to be using at current date. Better to retire it, before waiting for it to go "pop", with a chance of component frying.

And I suppose that should then get me through the next 10+ years.

If you get high-end PSU, then yes. E.g Seasonic PRIME, Corsair HXi/AXi, Super Flower Leadex Titanium/V Pro.
If you get cheaper PSU, not so much. E.g Seasonic B12/G12, Corsair CX/CS.

How important to do you see currently to get one with ATX 3.0 and the 12+4 pin connector? The article seems to suggest that it would be required for future GPUs but I'm not quite sold on that...

I'm not the one who would advocate getting ATX 3.0 PSU. ATX 2.0 PSUs are still fine to be used, especially good quality ones and if you're going to use RTX 30- or 40-series GPU, then there are adapters for that.

E.g my Seasonic PRIME TX-650 is ATX 2.0, but i can get adapter for newer GPUs. Also, while my PSU is 6 years old, it only has spent about half of it's life expectancy. So, i'm good for another 6 years for the very least. Though, high-end Seasonic units have shown that they can easily outlast their warranty period + then some. My PSU has 12 years of warranty. All Seasonic PRIME units actually have 12 years of warranty (longest there is in the world).

 

[strobolt]

Thanks for the very detailed answers!

If you get high-end PSU, then yes. E.g Seasonic PRIME, Corsair HXi/AXi, Super Flower Leadex Titanium/V Pro.
If you get cheaper PSU, not so much. E.g Seasonic B12/G12, Corsair CX/CS.

I was maybe planning to skimp a bit and go for a Corsair RM but do you think the HXi or Prime would be longer lasting? Do the higher 80+ standard translate roughly to the longetivity due to better quality parts? Seems like Titanium is ~100 USD premium on top of the Gold level and I don't really care about the few %-points better efficiency as I only run the computer for maybe 5 hours a week but for longetivity I'm willing to pay for.

Edit. Ok the premium for better standard is not that much, more like 30 USD for jump from Gold to Platinum and then another 30 to Titanium. The 100 was coming from an RM comparison which I guess isn't quite apples to apples with Seasonic Prime

 

[Aeacus]

Do the higher 80+ standard translate roughly to the longetivity due to better quality parts?

No.

PSU's efficiency doesn't equal to PSU's build quality. There are 80+ Bronze units out there that are far better quality than some 80+ Gold units. Also, there are even some 80+ Titanium units out there that are complete crap. Silverstone managed to create one such unit.

To make it easy for you, anything from Tier A will do fine,
PSU Tier list: https://forums.tomshardware.com/thr...er-list-rev-14-8-final-update-jul-21.3624094/

But what shows the PSU's longevity the best, would be the warranty given for it.
Few examples;
Be Quiet! Dark Power 11, despite being built well (Tier A), only has 5 years of warranty.
Corsair RMe has 7 years of warranty. So does Seasonic Core GX/GM/GC and Seasonic Focus GM.
Corsair RMx/RMi/HXi/AXi have 10 years of warranty. So does Seasonic Focus GX/PX. <- Most high-end PSUs have 10 years of warranty.
Seasonic PRIME GX/PX/TX have 12 years of warranty. <- Unique to Seasonic PRIME lineup. No other PSU OEM/brand offers more than 10 years of warranty.

Since after all, if manufacturer, e.g Be Quiet, doesn't trust their PSU to last longer than 5 years, hence giving only 5 year warranty, then why buy that PSU, while you could easily buy 10 or 12 year warranty PSU.

The 100 was coming from an RM comparison which I guess isn't quite apples to apples with Seasonic Prime

Corsair is big PSU brand with plenty of production. Then again, none of the Corsair PSUs are made by Corsair. Instead, Corsair buys their PSUs from PSU OEMs, including, but not limited to: HEC, Great Wall, Channel Well Technology, Seasonic, Flextronics. Due to that, Corsair can offer lower prices compared to smaller, but still good PSU OEMs, like Seasonic or Super Flower.

 

[strobolt]

To make it easy for you, anything from Tier A will do fine,
PSU Tier list: https://forums.tomshardware.com/thr...er-list-rev-14-8-final-update-jul-21.3624094/

But what shows the PSU's longevity the best, would be the warranty given for it.

Thanks again for a very good resource I was not aware of!

That's a good point regarding the warranty. For home appliences I prefer German brand Miele which offers 20 year warranty, even if they cost twice the amount of LG and others who typicaly offer like 5 years of warranty. For PSUs I was somehow assuming that they would all have similar warranties (like GPUs, CPUs or RAMs where the warranty is not really a consideration factor)

From that view-point I'm tempted to spring for the Seasonic Prime GX for the 12 year warranty, although it seems that the additional 2 years of warranty comes with a price premium of 20~30 % compared to the Seasonic Focus GX making it less enticing purely from financial point-of-view, assuming end-of-life at warranty period end.

But I suppose we're digressing purely to the PSU discussions for which I should probably take a look at the PSU section of the forum, I'm sure there are bound to be some interesting threads between the differences of the different A tier PSUs.

As for the original topic of this thread, it's clear that I should get a new PSU already now to ensure that I don't run into any issues with the current setup and provide flexibility for furture upgrades. And as a bonus then I get to throw the HX620 to an empty case and start building a secondary PC from the surplus parts left over from the upgrades

 

[Aeacus]

But I suppose we're digressing purely to the PSU discussions for which I should probably take a look at the PSU section of the forum, I'm sure there are bound to be some interesting threads between the differences of the different A tier PSUs.

You could start here,
topic: https://forums.tomshardware.com/thr...pply-discussion-thread-toms-hardware.3212332/

From that view-point I'm tempted to spring for the Seasonic Prime GX for the 12 year warranty, although it seems that the additional 2 years of warranty comes with a price premium of 20~30 % compared to the Seasonic Focus GX making it less enticing purely from financial point-of-view, assuming end-of-life at warranty period end.

Seasonic PRIME uses better PSU platform than Seasonic Focus. PRIME is flaship line of Seasonic, while Focus is more like "mid-tier", but in actuality, is still good PSU to use.

From the topic i linked;

Most common currently, in order of preference, would be the Seasonic Focus series, then Focus plus, then Prime, then Prime ultra. The newer Core series units are positioned as Core GC, Core GM and Core GX in order of heirarchy. It's worth mentioning that there are generally Gold, Platinum and Titanium versions within each, or most, of those series, but that does not necessarily mean that a Focus plus Platinum is necessarily better than a Prime Gold. It only means that it scored better in the 80plus efficiency testing, not that the platform is better.

Info in the topic is a bit old, since at that time, Seasonic was in process of renaming their PSUs for better understandability, known as OneSeasonic initiative.
Here's guide on what OneSeasonic is and how to understand the model naming scheme,
link: https://seasonic.com/oneseasonic

The 3 PCs i have, are powered by;
(old model name - part number - new model name - PC name)
Seasonic PRIME 650 80+ Titanium - SSR-650TD - Seasonic PRIME TX-650 - Skylake
Seasonic PRIME Ultra 650 80+ Titanium - SSR-650TR - Seasonic PRIME TX-650 - Haswell
Seasonic Focus Plus 550 80+ Platinum - SSR-550PX - Seasonic Focus PX-550 - AMD
Full specs with pics in my sig.

Though, to give you some rough idea between Seasonic Focus and PRIME units, it is similar to e.g GTX 1080 vs GTX 1080 Ti, whereby Ti version of the GPU is the better iteration of original SKU. Of course, better PSU doesn't give you more FPS, like Ti version of the GPU does. But it gives better voltage regulation, less ripple, bigger cooling fan and other aspects.

You can compare different Seasonic PSU models from their website: https://seasonic.com/consumer/power-supplies
E.g:

For PSUs I was somehow assuming that they would all have similar warranties (like GPUs, CPUs or RAMs where the warranty is not really a consideration factor)

In a nutshell, regarding PSU's warranty:
up to 2 years - terrible reliability
3 years - poor reliability (e.g Corsair VS/CS)
5 years - mediocre reliability (e.g Be Quiet! Straight Power 11, Seasonic G12, Corsair CX/CXF)
7 years - good reliability (e.g Seasonic Core/Focus GM, Corsair TX/AX)
10 years - great reliability (e.g Seasonic Focus GX/PX, Corsair RMx/HX/HXi/AXi)
12 years - superb reliability (e.g Seasonic PRIME)

Rest of PC components, usually, have 2 years of warranty when sold in EU (due to the laws here). Don't know how it is in the rest of the world, including USA. But that still doesn't mean hardware manufacturers can't showcase their product's reliability by longer warranties.

E.g all Noctua fans and CPU coolers have 6 year warranty.
Same goes to Arctic Cooling and their fans, CPU air and liquid coolers. All of them also have 6 years of warranty.
Corsair fans have 5 years warranty. AIOs have 2-6 years warranty, depending on a model.