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What’s wild is that this is a company clearly capable of designing highly complex things with numerous tradeoffs, challenges and unknowns. And then the fuckin cable is the issue. Repeatedly.
What’s wild is that this is a company clearly capable of designing highly complex things with numerous tradeoffs, challenges and unknowns. And then the fuckin cable is the issue. Repeatedly.
Ford Focus Mk3 and Prius Prime 2024.
Yup. The door had weird failure cases that needed a recall.
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Connectors and cables is damn near Masters level in knowledge and application. Its a rarely studied and often ignored piece of engineering. The more you learn about them, the crazier it gets.
That being said, this news that the 4090 and 5090 are using but one shunt resistor for all 6 power pins is horrifying to me. I'm not Power Engineer but it looks horrifyingly wrong to my napkin math.
People underestimate the problems of physical design or the design effort needed to make good designs.
You only paid $2000 for it, what did you expect.
Derbauer and Buildzoid on YouTube made nice informative videos on subject, and no it is not "simply a user error". So glad I went with 7900 XTX - should be all set for a couple of years.
Earlier quoted context omitted.
So then it would need to be significantly larger.
Likely smaller actually.
Your SMPS needs sub-2V output, cool. That means it only needs to accept small portions of the incoming.
But, if the incoming is 48V, it needs 48V tolerant parts. All your caps, inductor (optional typically), diodes, the SMPS itself.
Maybe there isn’t a sides difference in a 0603 50V capacitor and 10V 0603 capacitor, but there is a cost difference. And it definitely doesn’t get smaller just because.
Your traces at 48V likely need more space/separation or routing considerations that they would at 24V, but this should be a quickly resolved problem at your SMPS is likely right next to your connector.
Earlier quoted context omitted.
I doubt engineering a new connector (I think it's new? Unlike the Mini-Fit Jr which has been around for like 40-50 years) and standing up a supply chain for it could offset the potentially slightly lower BOM cost of using one specialty connector instead of three MiniFit Jr 8-pins. However, three of those would not have been enough for the 4090, nevermind the 5090.
> three of those would not have been enough for the 4090, nevermind the 5090. Oh you are right these PCIe power connectors can only draw 150W, so you would need 4 of those for 4090/5090. I guess that makes sense then to create a new standard for it actually, hopefully they can make a newer revision of that connector that makes it safer. In theory with the new standard you can have a single cable from the PSU to the G…
Derbauer and Buildzoid on YouTube made nice informative videos on subject, and no it is not "simply a user error". So glad I went with 7900 XTX - should be all set for a couple of years.
> TL;DW: The 3090 had 3 shunt resistors set up in a way which distributed the power load evenly among the 6 power-bearing conductors. That's why there were no reports of melted 3090s. The 4090/5090 modified the engineering for whatever reason, perhaps to save on manufacturing costs, and the shunt resistors no longer distribute the power load. Therefore, it's possible for 1 conductor to bear way more power than the rest, and that's how it melts.
> The only reason why the problem was considered "fixed" (not really, it wasn't) on the 4090 is that apparently in order to skew the load so much to generate enough heat to melt the connector you'd need for the plug to not be properly seated. However with 600W, as seen on der8auer video, all it takes is one single cable or two making a bit better contact than the rest to take up all the load and, as measured by him, reach 23A.
https://old.reddit.com/r/hardware/comments/1imyzgq/how_nvidi...
You only paid $2000 for it, what did you expect.
There is a real problem with the connector design somewhere: der8auer tested with his own RTX 5090FE and saw two of the cable strands reach concerning temperatures (>150ºC). Video timestamp: https://youtu.be/Ndmoi1s0ZaY?t=883
What’s wild is that this is a company clearly capable of designing highly complex things with numerous tradeoffs, challenges and unknowns. And then the fuckin cable is the issue. Repeatedly.
Reminds me a bit of BMWs and their infamous and persistent coolant pump woes. The running joke in those circles is "replacing the entire cooling system" counts as "basic, regular maintenance". BMW makes a fantastic engine, then makes the water pump impeller out of plastic. For what feels like decades.