Question Is it safe to use a 3 plug adapter on a 4090 even if it comes with a 4 plug one?

[YouFilthyHippo]

Most 4090's come with a 4 8-pin to 16-pin adapter. But PSU-ports are finite (Trying to install 2 4090's into one machine). is it safe to use a 3 8-pin instead of one that's 4? Or does it matter?

 

[rgd1101]

get a new psu

 

[hotaru.hino]

I'd err on the side of caution and say it's not.

You could do more research on your end if you really want to weigh your options though.

 

[bniknafs9]

there are some articles suggesting that they tend to get too hot , and melt down like an HDMI cable playing 8K . maybe you're safer using two 8 pin sets instead.

 

[ex_bubblehead]

If the PSU doesn't have the correct plug/s on it then it's too old to be used in that system. Replace it with a new one that does have the correct connectors.

 

[sonofjesse]

Just buy the correct cable. Corsair and bequite sell the cable for like 25 bucks

 

[ohio_buckeye]

Op……you are buying a $1600 dollar graphics card which is highway robbery honestly. Are you really going to risk that new card with a 30 dollar cable? Get a new power supply that’s quality and has the proper connections.

In other words don’t spend so much on the graphics card and then cheap out on the parts needed to run it. If a power supply goes out, depending on the quality, they can fry your card and possibly the rest of your pc.

 

[sonofjesse]

This 30 dollar cable is supported by the vendor lol.

Not everyone will have a 4090, for example I have a 4070TI.

All the guys at MC are using the corsair cable and RMX power supplies no issues.

 

[hotaru.hino]

While sure, you could say "have the correct equipment for the job", sometimes that's not always practical when the existing equipment can substitute for it just fine. It just has to be done correctly. I suggest reading this page: http://jongerow.com/12VHPWR/ because it clears up in detail things about using the 12VHPWR connector. Also keep in mind, the author of that article is Jon Gerow, AKA JonnyGuru.

 

[rgd1101]

People spend how much for a 4090 and OP getting 2. and try to cheap out on the PSU

 

[hotaru.hino]

We don't even know what PSU OP has. If, for example, OP has a Corsair AX1600i, just get two of these.

And if you want to slap me on the wrist for suggesting so, again, read Jon Gerow's article.

EDIT: Okay bad example of PSU give the other information, but you get the picture.

 

[Eximo]

My understanding is if you leave one of the 4 unplugged you will be power limited to the stock power settings. For rendering and the like that is probably desirable, don't really want the extra heat and overhead of high boost clocks.

Power supply details first though.

 

[DSzymborski]

This 30 dollar cable is supported by the vendor lol.

Not everyone will have a 4090, for example I have a 4070TI.

All the guys at MC are using the corsair cable and RMX power supplies no issues.

Did the vendor support it specifically to make more PCIE plugs available than it comes with? It's not enough for the cable to just exist.

If so, show your work.

 

[sonofjesse]

https://www.corsair.com/us/en/Categ...0-12VHPWR-Type-4-PSU-Power-Cable/p/CP-8920284

https://www.bequiet.com/en/accessories/3959

I can only speak for my personal experience. Talking with the guys at MicroCenter who several were running 4090's since they came out using this corsair cable.

I been using this cable with an HXI and 4070TI no issues.

Johnny Guru (now corsair) was on one of the main channels talking about this adapter specifically and how it would fine with your corsair ATX 2.0 power supply.

I personally prefer a direct cable like this, than the adapter cables that comes with the video cards.

If you have an ATX 3.0 spec power supply that has the newer cable built in even better! Just according to Johnny Guru that is not needed if you have a high quality power supply such as corsair and you can u se this cable directly.

YMMV, just sharing my personal experience.

If I was installing two 4090's I would either run two power supplies or have a very beefy one to handle the spikes.

 

[SyCoREAPER]

First, I'm not going to even ask why you need two 4090's.

Second, I won't ask why you can afford 2 4090's but not a decent power supply.

I will however ask a question and make a statement.

Question: Why would you do something as foolish as play roulette by not supplying the cards with what they are designed for? Being 4 non-looped PCIe connectors each.

Statement: If you are that limited and are dead set on using whatever PSU you have, sell your 4090s and get 4090's that use 3-plug to 12VHPWR out of the box such as MSI Gaming Trio.

 

[Karadjgne]

4090's are 450w cards nominally. That's just fine with 3x 8pins as a 8pin is rated for 150w, but in reality can handle closer to 180w. The card knows how much power is supplied. If the card senses the 4th 8pin, it loosens up the power limits and allows anywhere upto 600w, depending on the manufacturer, but generally is closer to 520w.

If using the cards for production work, better to keep them at the 450w limits anyway, the gains due to the higher boosts aren't offset by the heat/power requirements of the higher boosts.

 

[SyCoREAPER]

4090's are 450w cards nominally. That's just fine with 3x 8pins as a 8pin is rated for 150w, but in reality can handle closer to 180w. The card knows how much power is supplied. If the card senses the 4th 8pin, it loosens up the power limits and allows anywhere upto 600w, depending on the manufacturer, but generally is closer to 520w.

If using the cards for production work, better to keep them at the 450w limits anyway, the gains due to the higher boosts aren't offset by the heat/power requirements of the higher boosts.

Relying on software, is a dangerous game. Since the exact model isn't in the OP, if the software fails, malfunctions or otherwise, you now have no protection/buffer if using a 3 plug adapter. If those cards suddenly try and draw 600w+ power, best case the PSU trips (confidence isn't high in that happening considering OP doesn't want to spend money for a proper PSU apparently). Mid-worst case the wires from the PSU burn up and the cards are fine. Worst case OP might not notice until the heat buildup from the now overloaded wiring or rail is so great that it melts the connectors on the cards. Game Over.

 

[Karadjgne]

It's not software or firmware. It's hardware. 6/8pin aren't just 12v+ and G pins, there's also sensor wires. It's how any gpu detects the difference between a 6 and 8, if that sensor in the 8 isn't connected, its a 6 to the gpu, so only pulls 75w not the full 150w. Same applies to using correct cables in a 3 or 4 connection, if the sensor in the 4th isn't connected, it's a 3 to the gpu, so can't pull the upto 600w, it's power limited to 450w at the psu.

A 4090 is a 450w with a bonus 150w if available, it's not a 600w card by default.

 

[DSzymborski]

This would be a great time for the original poster to actually say what their PSU is, because we're all arguing theoreticals since the initial question was woefully lacking in actual information provided about this situation.

 

[Karadjgne]

Entire system specs would be more appropriate, you aren't putting 2x 4090 in a pc with a i9 on even a 1600w AXi without severe power limitations in place.

 

[SyCoREAPER]

@Karadjgne
That is assuming the adapter's sense pins are wired correctly. I was referring to the likes of Afterburner to limit wattage.

This would be a great time for the original poster to actually say what their PSU is, because we're all arguing theoreticals since the initial question was woefully lacking in actual information provided about this situation.

Agreed. Let's let's this thread just sit until OP gives full system specs, what they are doing, etc..