600W PCIe 5.0 12VHPWR Type-4 PSU Power Cable Compatibility with RMX 850 PSU

[ChrisFR91]

Hello, new here, i would like understand the concept "600W" of  PCIe 5.0 12VHPWR Type-4 PSU Power Cable. is it a maximum admissible power ?

I bought an RMX 850 watt in following the MSI recommendations for my RTX 3090TI SUPRIMX card. 

The power cable is 3x PCI-Express 6+2 Pins to 12 Pins 12VHPWR, so uses 3 ports, and if i understand 450 watts power in max. 

In context can I swapp this cable 3 ports with 12VHPWR Type 4 Power Cable that use 2 ports 8 Pins EPS 12V ? My power supply is enough ?

thank you all

[LeeGodfrey]

I have a similer query, Can I use a RTS 4090 with my

Corsair HX850 Platinum 850 W 80+ Platinum

[Pocah]

Corsair actually say that the limit for the cable on an 850W power supply is 300W.  But as far as I can see this is a user limit, in that it is not enforced by the sense lines in the cable itself, so you could happily plug the cable in to an HX850 giving you anything up to a 600W draw. You need to use your brains to figure that you shouldn't actually do that, you should buy a new power supply if you actually need 600W. But certainly for 450W then it should be OK on an 850W psu. Personally, I would be happier though if you followed the recommendation of the GPU manufacturer - which are usually around 1000W for the PSU.  I mean, lets be honest here, if you can afford a 4090 then you can afford a new PSU. 

If I am wrong about this ( and I could well be ) then I really would be interested to hear a response from Corsair ( since I would like to know how the sense lines on the cable know what power supply you have!!).  

 

Edited October 23, 2022 by Pocah

[LeDoyen]

from what i understood from gamers nexus video, it doesn't sense what PSU you have, it really can't anyway. It's more of a sensing of ho many cables are connected.

the GPU receives a signal when a cable is connected. On the 4 cable squid, if one of the 4 cables is removed, the GPU senses it and sticks to PCIE specs, not allowing more than 450W (150W per PCIE cable. the GPU will work but not allow any boosting past 450W). 

On the corsair cable, i believe it's the same but with two 300W legs. if one is disconnected, the GPU will see it can pull only 300W and will either downclock massively or simply not turn on.