• Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

ATX 3.0 PSU Specification Loophole Lets Manufacturers Evade Stringent Excursion Tolerance Testing by Simply Excluding the 12+4 pin Connector

btarunr

Editor & Senior Moderator
Staff member
Joined
Oct 9, 2007
Messages
47,288 (7.53/day)
Location
Hyderabad, India
System Name RBMK-1000
Processor AMD Ryzen 7 5700G
Motherboard ASUS ROG Strix B450-E Gaming
Cooling DeepCool Gammax L240 V2
Memory 2x 8GB G.Skill Sniper X
Video Card(s) Palit GeForce RTX 2080 SUPER GameRock
Storage Western Digital Black NVMe 512GB
Display(s) BenQ 1440p 60 Hz 27-inch
Case Corsair Carbide 100R
Audio Device(s) ASUS SupremeFX S1220A
Power Supply Cooler Master MWE Gold 650W
Mouse ASUS ROG Strix Impact
Keyboard Gamdias Hermes E2
Software Windows 11 Pro
When testing recent high-end GPU launches such as the AMD Radeon RX 6950 XT graphics card, we observed some system reboots that caused due to power-draw spikes (technically known as "excursions"). This is when a graphics card, for a brief moment, draws more power than the connector is capable of supplying, triggering the PSU's electrical protections, and causing a reboot. The new ATX 3.0 specification for the next-generation of desktop PC power supplies enable PSUs with a high tolerance for excursions, and prescribes testing standards to ensure a PSU meets the ATX 3.0 spec. Aris Mpitziopoulos (crmaris) and Jon Gerow (Jonnyguru) discovered wording in the latest Intel ATX 3.0 specification that could make you pay closer attention to reviews of ATX 3.0-spec PSU, when they're out.

In a Hardware Busters article, Mpitziopoulos clears the confusion that the ATX 3.0 power supply specs by Intel and the PCI-Express 5.0 power specification by the PCI-SIG, are mutually-inclusive—they're not. An ATX 3.0 PSU is not required to include a 12+4 pin (or 16-pin) ATX 12VHPWR connector, whether or not their nameplate Wattage is above 450 W, which means it's subjected to passing less stressful transient-response tests, particularly the ability to deal with a 200% excursion for at least 100 µs.



The ATX 3.0 also introduces a feature called Alternative Low Power Mode (ALPM), which is hardware-level preparation for OS-level system low-power device states, such as Windows 10 Modern Standby and ChromeOS Lucid Sleep. The ATX 3.0 spec had prescribed certain new hold-up time requirements for PSUs offering ALPM, however it was discovered that these specs only apply to the 3.3 V rail, and not the all-important 12 V.


Put simply, the vagueness in Intel's specs allow the manufacturer of a cheap/mainstream PSU to claim ATX 3.0 readiness by excluding a 12VHPWR connector at any nameplate-Wattage, just so they can evade the steep transient-response testing required to include such a connector. It allows them to [over]compensate with a large number of conventional 150-Watt 8-pin PCIe connectors, and hope that people use cables included with their next-generation graphics cards that convert a number of PCIe connectors into a high-Wattage 12+4 pin connector.

View at TechPowerUp Main Site | Source
 
Joined
Dec 28, 2012
Messages
3,944 (0.90/day)
System Name Skunkworks 3.0
Processor 5800x3d
Motherboard x570 unify
Cooling Noctua NH-U12A
Memory 32GB 3600 mhz
Video Card(s) asrock 6800xt challenger D
Storage Sabarent rocket 4.0 2TB, MX 500 2TB
Display(s) Asus 1440p144 27"
Case Old arse cooler master 932
Power Supply Corsair 1200w platinum
Mouse *squeak*
Keyboard Some old office thing
Software Manjaro
Oh no! like, all 3 people out there with a 12v board are going to be so inconvenienced :laugh: :roll: :laugh:

Meanwhile the rest of us wont have issues because we still use the 24 pin connector, like the rest of the AIB industry.
 

btarunr

Editor & Senior Moderator
Staff member
Joined
Oct 9, 2007
Messages
47,288 (7.53/day)
Location
Hyderabad, India
System Name RBMK-1000
Processor AMD Ryzen 7 5700G
Motherboard ASUS ROG Strix B450-E Gaming
Cooling DeepCool Gammax L240 V2
Memory 2x 8GB G.Skill Sniper X
Video Card(s) Palit GeForce RTX 2080 SUPER GameRock
Storage Western Digital Black NVMe 512GB
Display(s) BenQ 1440p 60 Hz 27-inch
Case Corsair Carbide 100R
Audio Device(s) ASUS SupremeFX S1220A
Power Supply Cooler Master MWE Gold 650W
Mouse ASUS ROG Strix Impact
Keyboard Gamdias Hermes E2
Software Windows 11 Pro
Oh no! like, all 3 people out there with a 12v board are going to be so inconvenienced :laugh: :roll: :laugh:

Meanwhile the rest of us wont have issues because we still use the 24 pin connector, like the rest of the AIB industry.

Future high-end Gen5 graphics cards will inflict excursions. If you use a PSU that doesn't meet those tolerances, your system will randomly reboot when gaming.
 
Joined
Dec 28, 2012
Messages
3,944 (0.90/day)
System Name Skunkworks 3.0
Processor 5800x3d
Motherboard x570 unify
Cooling Noctua NH-U12A
Memory 32GB 3600 mhz
Video Card(s) asrock 6800xt challenger D
Storage Sabarent rocket 4.0 2TB, MX 500 2TB
Display(s) Asus 1440p144 27"
Case Old arse cooler master 932
Power Supply Corsair 1200w platinum
Mouse *squeak*
Keyboard Some old office thing
Software Manjaro
Future high-end Gen5 graphics cards will inflict excursions. If you use a PSU that doesn't meet those tolerances, your system will randomly reboot when gaming.
MMMmmm.... jus tlike nvidia's 12 pin connector that never saw use outside of nvidia founder cards?

Something tells me the industry is gonna stick with the usual 8 pin for awhile yet.
 
Joined
Jul 9, 2016
Messages
1,081 (0.35/day)
System Name Main System
Processor i9-10940x
Motherboard MSI X299 Xpower Gaming AC
Cooling Noctua NH-D15S + Second Fan
Memory G.Skill 64GB @3200MHz XMP
Video Card(s) ASUS Strix RTX 3090 24GB
Storage 2TB Samsung 970 EVO Plus; 2TB Corsair Force MP600; 2TB Samsung PM981a
Display(s) Dell U4320Q; LG 43MU79-B
Case Corsair A540
Audio Device(s) Creative Lab SoundBlaster ZX-R
Power Supply EVGA G2 1300
Mouse Logitech MK550
Keyboard Corsair K95 Platinum XT Brown Switches
Software Windows 10 Pro
Benchmark Scores Cinebench R20 - 6910; FireStrike Ultra - 13241; TimeSpy Extreme - 10067; Port Royal - 13855
So if a PSU does not have the 12+4 pin, then don’t buy it, am I reading this right?
 

btarunr

Editor & Senior Moderator
Staff member
Joined
Oct 9, 2007
Messages
47,288 (7.53/day)
Location
Hyderabad, India
System Name RBMK-1000
Processor AMD Ryzen 7 5700G
Motherboard ASUS ROG Strix B450-E Gaming
Cooling DeepCool Gammax L240 V2
Memory 2x 8GB G.Skill Sniper X
Video Card(s) Palit GeForce RTX 2080 SUPER GameRock
Storage Western Digital Black NVMe 512GB
Display(s) BenQ 1440p 60 Hz 27-inch
Case Corsair Carbide 100R
Audio Device(s) ASUS SupremeFX S1220A
Power Supply Cooler Master MWE Gold 650W
Mouse ASUS ROG Strix Impact
Keyboard Gamdias Hermes E2
Software Windows 11 Pro
So if a PSU does not have the 12+4 pin, then don’t buy it, am I reading this right?
If a PSU yells "ATX 3.0" on the tin and lacks 12+4 pin connector, pay attention to its reviews, or choose another PSU that has one.
 
Joined
Apr 24, 2021
Messages
281 (0.21/day)
So in other words, when buying an "ATX3.0" power supply make sure to get a version with the the new 12+4 pin connector... and ignore all else.

Does anyone understand why certain standards setting bodies include vague requirements and/or loopholes? I mean look at the USB nightmare. USB3.0, USB 3.1, USB 3.2 Gen1/Gen2/Gen2x2. What the actual F. Why not just simple labeling: USB 3 (5, 10, 20 Gbps)?

And in regards to power supplies, do some of the member companies like Nvidia, PSU manufacturers etc., have too much sway into the language of the standards... so as to not negatively impact future sales?

I can't understand why some PSUs that don't have to undergo the stringent testing requirements are able to be considered "ATX3.0"?

What's the functional difference between existing ATX2.x PSUs (e.g., Corsair RMx1000) and an "ATX3.0" PSU (that lacks the 12+4 pin) connector?
 
Last edited:
Joined
Jun 19, 2010
Messages
409 (0.08/day)
Location
Germany
Processor Ryzen 5600X
Motherboard MSI A520
Cooling Thermalright ARO-M14 orange
Memory 2x 8GB 3200
Video Card(s) RTX 3050 (ROG Strix Bios)
Storage SATA SSD
Display(s) UltraHD TV
Case Sharkoon AM5 Window red
Audio Device(s) Headset
Power Supply beQuiet 400W
Mouse Mountain Makalu 67
Keyboard MS Sidewinder X4
Software Windows, Vivaldi, Thunderbird, LibreOffice, Games, etc.
An ATX 3.0 PSU is not required to include a 12+4 pin (or 16-pin) ATX 12VHPWR connector, whether or not their nameplate Wattage is above 450 W, which means it's subjected to passing less stressful transient-response tests, particularly the ability to deal with a 200% excursion for at least 100 ms. "Should be 100 µs" like in the shown table, right?
 
Joined
Oct 16, 2019
Messages
24 (0.01/day)
Even without 12VHPWR connector, PSU must work with 150% power excursion, if it wants to be certified to ATX 3.0 spec.
Some older PSUs did shutdown with even slightest overload.
 
Joined
Feb 20, 2020
Messages
9,340 (5.30/day)
Location
Louisiana
System Name Ghetto Rigs z490|x99|Acer 17 Nitro 7840hs/ 5600c40-2x16/ 4060/ 1tb acer stock m.2/ 4tb sn850x
Processor 10900k w/Optimus Foundation | 5930k w/Black Noctua D15
Motherboard z490 Maximus XII Apex | x99 Sabertooth
Cooling oCool D5 res-combo/280 GTX/ Optimus Foundation/ gpu water block | Blk D15
Memory Trident-Z Royal 4000c16 2x16gb | Trident-Z 3200c14 4x8gb
Video Card(s) Titan Xp-water | evga 980ti gaming-w/ air
Storage 970evo+500gb & sn850x 4tb | 860 pro 256gb | Acer m.2 1tb/ sn850x 4tb| Many2.5" sata's ssd 3.5hdd's
Display(s) 1-AOC G2460PG 24"G-Sync 144Hz/ 2nd 1-ASUS VG248QE 24"/ 3rd LG 43" series
Case D450 | Cherry Entertainment center on Test bench
Audio Device(s) Built in Realtek x2 with 2-Insignia 2.0 sound bars & 1-LG sound bar
Power Supply EVGA 1000P2 with APC AX1500 | 850P2 with CyberPower-GX1325U
Mouse Redragon 901 Perdition x3
Keyboard G710+x3
Software Win-7 pro x3 and win-10 & 11pro x3
Benchmark Scores Are in the benchmark section
Hi,
Talking about high end gpu's and referring to a lower powered 450w psu is pretty funny comparison to me frankly :kookoo:

Not to mention most spec's say 850w recommended.
 
Joined
Jul 15, 2020
Messages
1,021 (0.63/day)
System Name Dirt Sheep | Silent Sheep
Processor i5-2400 | 13900K (-0.02mV offset)
Motherboard Asus P8H67-M LE | Gigabyte AERO Z690-G, bios F29e Intel baseline
Cooling Scythe Katana Type 1 | Noctua NH-U12A chromax.black
Memory G-skill 2*8GB DDR3 | Corsair Vengeance 4*32GB DDR5 5200Mhz C40 @4000MHz
Video Card(s) Gigabyte 970GTX Mini | NV 1080TI FE (cap at 50%, 800mV)
Storage 2*SN850 1TB, 230S 4TB, 840EVO 128GB, WD green 2TB HDD, IronWolf 6TB, 2*HC550 18TB in RAID1
Display(s) LG 21` FHD W2261VP | Lenovo 27` 4K Qreator 27
Case Thermaltake V3 Black|Define 7 Solid, stock 3*14 fans+ 2*12 front&buttom+ out 1*8 (on expansion slot)
Audio Device(s) Beyerdynamic DT 990 (or the screen speakers when I'm too lazy)
Power Supply Enermax Pro82+ 525W | Corsair RM650x (2021)
Mouse Logitech Master 3
Keyboard Roccat Isku FX
VR HMD Nop.
Software WIN 10 | WIN 11
Benchmark Scores CB23 SC: i5-2400=641 | i9-13900k=2325-2281 MC: i5-2400=i9 13900k SC | i9-13900k=37240-35500
Joined
Jul 16, 2014
Messages
8,215 (2.16/day)
Location
SE Michigan
System Name Dumbass
Processor AMD Ryzen 7800X3D
Motherboard ASUS TUF gaming B650
Cooling Artic Liquid Freezer 2 - 420mm
Memory G.Skill Sniper 32gb DDR5 6000
Video Card(s) GreenTeam 4070 ti super 16gb
Storage Samsung EVO 500gb & 1Tb, 2tb HDD, 500gb WD Black
Display(s) 1x Nixeus NX_EDG27, 2x Dell S2440L (16:9)
Case Phanteks Enthoo Primo w/8 140mm SP Fans
Audio Device(s) onboard (realtek?) - SPKRS:Logitech Z623 200w 2.1
Power Supply Corsair HX1000i
Mouse Steeseries Esports Wireless
Keyboard Corsair K100
Software windows 10 H
Benchmark Scores https://i.imgur.com/aoz3vWY.jpg?2
the ATX 3.0 power supply specs by Intel and the PCI-Express 5.0 power specification by the PCI-SIG, are mutually-inclusive—they're not.
Its been shady right from the start it seems, kinda like Privacy EULAs.
 

Oshadorin

New Member
Joined
May 12, 2022
Messages
10 (0.01/day)
The Asus ROG Thor II lineup, announced 10 months ago, is still barely available anywhere, and do not have a native 12+4 pin connector, only an adapter. Whereas the lower tier ROG Loki lineup, do have the native PCI-E 5.0 connector. There is definitely a problem without production of RTX 3.0 PSU.
 
Joined
Sep 23, 2021
Messages
94 (0.08/day)
MMMmmm.... jus tlike nvidia's 12 pin connector that never saw use outside of nvidia founder cards?

Something tells me the industry is gonna stick with the usual 8 pin for awhile yet.
Nvidia's 12 pin connector was a one-off, brand exclusive that they tried for a single generation of GPUs, and not even all the GPUs of that gen. The 16 pin 12VHPWR is specified by PCI-SIG, an industry-wide consortium that sets (among other things) connector standards.

Scream and cry all you want, but the 16 pin is going to be the new standard, just like USB-C replacing USB-A.
 
Joined
Aug 25, 2022
Messages
159 (0.19/day)
Location
too close to Russian borders
System Name Phat Cat
Processor Ryzen 7 5700x3d
Motherboard MSI B550 Pro
Cooling ID Cooling SE-224XT with 120mm Noctua, 2x200mm Noctua front, 2x140 Noctua back and inside
Memory 32GB Kingston Fury 3200mhz CL16
Video Card(s) Asus RTX 3070 TUF OC
Storage Kingston NV2 256GB boot + Kingston NV2 2 TB storage
Display(s) Dell G3223D
Case Thermaltake Commander C32
Audio Device(s) Audigy 5/RX for optical SPDIF out to Audigy 2 Bay + Sennheiser HD569
Power Supply Thermaltake Toughpower GF1-750W
Software Windoze 11
Real soon we should see 1 Farad capacitors like the ones used in auto amps.
That is one cheap way to get rid of the spikes.

1661794353216.png
 
Joined
Dec 12, 2020
Messages
1,755 (1.20/day)
Bypass capacitors can get rid of spikes (and dips I guess) but I thought the problem being addressed here wasn't so much spikes as dips in supply voltage.
 
Joined
Apr 24, 2007
Messages
305 (0.05/day)
Location
Bay Area, CA
Oh no! like, all 3 people out there with a 12v board are going to be so inconvenienced :laugh: :roll: :laugh:

Meanwhile the rest of us wont have issues because we still use the 24 pin connector, like the rest of the AIB industry.
Wow. You've been here for 10 years and don't know the difference between ATX12VO and 12VHPWR?

Oh no! like, all 3 people out there with a 12v board are going to be so inconvenienced :laugh: :roll: :laugh:

Meanwhile the rest of us wont have issues because we still use the 24 pin connector, like the rest of the AIB industry.

"Something".

So in other words, when buying an "ATX3.0" power supply make sure to get a version with the the new 12+4 pin connector... and ignore all else.

Does anyone understand why certain standards setting bodies include vague requirements and/or loopholes? I mean look at the USB nightmare. USB3.0, USB 3.1, USB 3.2 Gen1/Gen2/Gen2x2. What the actual F. Why not just simple labeling: USB 3 (5, 10, 20 Gbps)?

And in regards to power supplies, do some of the member companies like Nvidia, PSU manufacturers etc., have too much sway into the language of the standards... so as to not negatively impact future sales?

I can't understand why some PSUs that don't have to undergo the stringent testing requirements are able to be considered "ATX3.0"?

What's the functional difference between existing ATX2.x PSUs (e.g., Corsair RMx1000) and an "ATX3.0" PSU (that lacks the 12+4 pin) connector?

My attitude is: If Cybenetics or Intel (or whatever 3rd party that can test to the spec) doesn't say it's ATX 3.0 compliant or even PCIe 5.0 compliant, don't believe it.

Real soon we should see 1 Farad capacitors like the ones used in auto amps.
That is one cheap way to get rid of the spikes.

View attachment 259921

I thought the same thing... but then realized the inrush just to charge the cap would shut down the PSU before you even had a chance to POST! :D :D :D
 
Joined
Dec 12, 2020
Messages
1,755 (1.20/day)
Wouldn't it be possible to limit the inrush current to the capacitor by using a series resistor?
 
Top