Modded RTX 5090 ditches 16-pin power for triple 8-pin connectors — draws up to 900W and hits 3,400 MHz

A modified Galax RTX 5090 graphics card with triple 8-pin PCIe power connectors — (Image credit: TecLab)

Modders at the YouTube channel TecLab have created what is being called the world’s first RTX 5090 powered by traditional 8-pin PCIe connectors. Not only were the modders able to successfully power up the graphics card, but they also proved that the older connector is still quite capable of handling the extreme power demands of a modern high-end GPU.

The card chosen for the experiment was a Galax GeForce RTX 5090D HOF OC LAB XOC, which is a top-of-the-line model that features a beefy cooler as well as dual 16-pin power connectors. The modders essentially dismantled the entire graphics card along with the dual 16-pin power connectors, stripping it down to just the bare PCB. Next, three 8-pin power connectors were installed at the rear, with each connector soldered directly to the power regulators on the PCB using heavy-gauge cables. Additionally, the sense pins had to be rewired to ensure that the card could reach its maximum power load without any restrictions. To keep the temperatures in check, they used a liquid cooling system with a GPU block.

An 8-pin PCIe power connector is officially rated for 150W, although its actual maximum capacity is much higher. During the one-hour livestream, the modders tested the GPU by gradually increasing the power draw, starting at 400W and going all the way up to 900W using three 8-pin power cables. At its peak, the modified RTX 5090 pulled more than 120A, with clock speeds reaching as high as 3,400 MHz. Notably, the mod was limited to only the hardware level, with no software or BIOS tweaks performed.

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Despite the PCI-SIG (PCI Special Interest Group) revising the 16-pin power connector (12V-2x6) to improve reliability, reports of melting GPU connectors continue to haunt gamers. The issue is particularly more common among high-performance models, though not limited to Nvidia RTX 50 and RTX 40 series, as certain AMD Radeon graphics with the 16-pin connector are also at risk. TecLab's experiment shows that GPU manufacturers may want to reconsider the tried-and-tested 8-pin connector and explore whether it could still be a viable option in high-end graphics cards.

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Kunal Khullar is a contributing writer at Tom’s Hardware. He is a long time technology journalist and reviewer specializing in PC components and peripherals, and welcomes any and every question around building a PC.

45 Comments Comment from the forums

Dementoss

Improving efficiency, so high performance GPUs don't need so much power would help.
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Vicecrow

Dementoss said:
Improving efficiency, so high performance GPUs don't need so much power would help.
I'am using the RTX 5070 at 2600mhz with 0.895v From 250w to 170w v-sync locked at 60hz modern games 2560x1400 uses about 130w of power.
These GPUS are efficient but always they want Bigger numbers on end of day.
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Cmdr_Scotty

Who woulda thought, the 8 pin connector needed no revision after all...
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re3eyul

funny how I haven't burned a cable or GPU connector since I powered my lab with a proper 30A 250v regulated PDU. domestic electric supply is made for dryers and convection ovens , not 900w GPU's , you guys are driving Ferraris on dirt roads and wondering why you bust rims in potholes
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usertests

Finally, a GPU suited for DLSS 5.
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MrN8

I agree the domestic power grid delivers dirty power. I used to get frequent crashes and OS instability and nearly pulled my hair out trying to figure out why. I tried everything I could and eventually brought the machine to a shop to be checked over. The crashes and instability didn't occur at the shop and they gave my PC a clean bill of health. After getting it home and setting it up, the system crashed on me again within minutes. I called the shop and we talked for a while and then the technician pointed out that they use a UPS with a pure sign wave power conditioner in their shop to deliver clean power to their test benches. He suggested dirty power from the grid could cause the issues. I searched around online, and found a UPS with pure sign power conditioning and ordered it. Ever since I started using it, my system is stable. Depending on where you live, age of wiring in your house or poor grid infrastructure in your area, your grid power can fluctuate in frequency and in some cases even have micro "brownouts" where supply disconnects and reconnects in microseconds which can reek havoc on sensitive electronics. I bet most of the people who have melted 16 connectors were plugged directly to the grid with dirty grid power.
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re3eyul

MrN8 said:
I agree the domestic power grid delivers dirty power. I used to get frequent crashes and OS instability and nearly pulled my hair out trying to figure out why. I tried everything I could and eventually brought the machine to a shop to be checked over. The crashes and instability didn't occur at the shop and they gave my PC a clean bill of health. After getting it home and setting it up, the system crashed on me again within minutes. I called the shop and we talked for a while and then the technician pointed out that they use a UPS with a pure sign wave power conditioner in their shop to deliver clean power to their test benches. He suggested dirty power from the grid could cause the issues. I searched around online, and found a UPS with pure sign power conditioning and ordered it. Ever since I started using it, my system is stable. Depending on where you live, age of wiring in your house or poor grid infrastructure in your area, your grid power can fluctuate in frequency and in some cases even have micro "brownouts" where supply disconnects and reconnects in microseconds which can reek havoc on sensitive electronics. I bet most of the people who have melted 16 connectors were plugged directly to the grid with dirty grid power.

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BillyBuerger

I don't think this really proves anything. They hacked together one example where the 8pin connectors survived for some time. But if you did this in a commercial card and had thousands of people using them, I'm sure you'd see similar failures still happening. 8-pin connectors are designed for 150W and they are running them at 300W. That's the same issue with the 12V HPWR/2x6 connector so the same issue still exists and fires would still happen.
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re3eyul

exactly , I have a 25Kw electric furnace on the same panel as my lab , when these induction loads start up ..... well anyone familiar with ohms law can imagine what happens to the other nema-30/15 circuits I have in the house , this is why the regulated power distribution , absolutely guaranteed pure 250v down to under a % . got 2 dozens mi60 running off that , saves expensive burn outs because of stupid reasons .
Reply
Eximo

BillyBuerger said:
I don't think this really proves anything. They hacked together one example where the 8pin connectors survived for some time. But if you did this in a commercial card and had thousands of people using them, I'm sure you'd see similar failures still happening. 8-pin connectors are designed for 150W and they are running them at 300W. That's the same issue with the 12V HPWR/2x6 connector so the same issue still exists and fires would still happen.

A more realistic rating for each 12V wire in PCIe connectors is 60W. So a six pin is closer to 120W and an 8-pin 180W. (And that is 18 gauge wire, not the commonly used 16 gauge in higher end units) That huge margin is why they don't burn up. 12VHPWR connectors cut that margin down to almost nothing and the smaller contact points make for some high potential resistance. The updated 12V 2x6 connector is a little more idiot proof and should have more contact area in the pins, but certainly still has the same low safety margin.

It has been mentioned many times, but if they had implemented some sort of load balancing for the wires, this would not be much of a problem. Only a few cards and power supplies have implemented per-wire monitoring, which is a step in the right direction.
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