PSU 850w enough for Threadripper and RTX 4080?

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SLP Firehawk

Limp Gawd
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Jan 30, 2020
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Hello.
I have this:
PSU: Corsair RM Series RM850 80 PLUS
CPU: Threadripper 3970X (280watts)
192GB 3200Mhz RAM
Several SSD drives

I want to install this GPU: RTX 4080 (320watts)

Apart from not having a native power connector do you think it will work? Or should I get another PSU that is ATX 3.0 with Dedicated PCIe 5.0 Connector?
I do not know much about this but realize the GPU has a new connnector and draws a lot of power.
The 4080 comes with an adapter cable that splits to three 8 pin cables for older PSUs. I'm not sure exactly where to plug those in on the PSU
 

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Should be fine as long as you are not overclocking. You use 3 pcix 6+2 cables from psu to adapter. A 6+2 cable is basically an 8pin pcie cable that can also be used as pcie 6 pin pcie
 
Thank you. While on this subject, since I originally received my PC it has the boot message attached below. And there has always been a cable not connected. I'm not sure if it was supposed to be connected or what the deal is. The GPU shipped and installed in the pic is RTX 3060 though I am considering swapping it to the card in the OP
 

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SLP Firehawk said:
I do not want to OC.
3 cables like this?
https://www.corsair.com/us/en/Categories/Products/Accessories-|-Parts/PC-Components/Power-Supplies/Type-3-Flat-Black-Ribbon-Cable-PCIe-6+2-pin,-dual-connectors,-Compatible-with-all-type-3-pin-out-PSU/p/CP-8920129
Click to expand...

Do you not have extra cables with the PSU that came with the system? Those cables are basically the right cable except they are type 3 and you want type 4 corsair cables like this: https://www.corsair.com/us/en/Categ...or-and-capacitors-for-Type-4-PSU/p/CP-8920143

As for the boot message it sound like you are maybe missing one or more of the CPU 8 pin cables. What model is your motherboard and can you post a screenshot from around the CPU socket area?
 
What does this cable say on both sides here. Does it say Type 4 on one side and CPU on the other?
where does the other end go to?

1672364648191.png
 
The only thing it says is 34-0 and 00277 on the PSU end. It goes around the back and ends up plugging into the top left of the MB. Looks like a matching one plugs into the top right of the MB. So it appears only the top right one is actually connected to both PSU and MB whereas the cable in question is plugged into the MB but disconnected at the PSU. Hmmm
 

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SLP Firehawk said:
The only thing it says is 34-0 and 00277 on the PSU end. It goes around the back and ends up plugging into the top left of the MB. Looks like a matching one plugs into the top right of the MB. So it appears only the top right one is actually connected to both PSU and MB whereas the cable in question is plugged into the MB but disconnected at the PSU. Hmmm
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Ok so that is probably why you get the post message you do because that is an 8 pin or 4x4 pin CPU cable. If you unplug the other one on the PSU side does it have the same numbering? If so then plug the unplugged one in here:
1672367544391.png
 
Edit I just mean to unplug it to ensure its a match for the connected CPU 8pin cable. It should be but an unplugged cable on a system I didn't put together would make me a bit nervous. Your board wants both CPU 8 pin cables connected in addition to the 24pin . After unplugging to make sure the numbering on the cables is the same you would plug them both back into teh PSU
 
motqalden said:
Edit I just mean to unplug it to ensure its a match for the connected CPU 8pin cable. It should be but an unplugged cable on a system I didn't put together would make me a bit nervous. Your board wants both CPU 8 pin cables connected in addition to the 24pin . After unplugging to make sure the numbering on the cables is the same you would plug them both back into teh PSU
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Thank you. That makes sense. It should have both 8 pin cables connected in addition to the 24 pin, but one of the 8 pin was left disconnected for some reason.
 
SLP Firehawk said:
Thank you. That makes sense. It should have both 8 pin cables connected in addition to the 24 pin, but one of the 8 pin was left disconnected for some reason.
Click to expand...
Yes exactly. And most systems don't even need both 8 pins but higher end core count motherboards often need the second one if you are gonna push it / OC. That is why despite the message on boot post, you are assumably able to run it.

1672369261586.png




The 3 on the left are all plugs for 8 pin or 6+2 pin PCIE. The two under the 24 pin on the right would be the cpu 8 pin, 4x4. I think on the psu end anyways you can plug either or into those 5 available slots. The cable will only go in one way on the motherboard end and that is also foolproof by the sizing and plug orientation. The main thing if you need to procure a given cable type is that it's corsair type 4 cable and either cpu 4x4 or pcie 6+2 or 8.
 
By the way I kinda love your Gskill Royal ram but why 6 sticks? someone will correct me if I am wrong here but this means you are only using 3 of 4 possible memory lanes in terms of bandwidth. Now mind you depending on what you use the computer for you may not need all the bandwidth but in some cases with your CPU and certain work loads you could use it.

Edit: oh is your AIO covering one of the ram slots? thats probably why
 
motqalden said:
By the way I kinda love your Gskill Royal ram but why 6 sticks? someone will correct me if I am wrong here but this means you are only using 3 of 4 possible memory lanes in terms of bandwidth. Now mind you depending on what you use the computer for you may not need all the bandwidth but in some cases with your CPU and certain work loads you could use it.

Edit: oh is your AIO covering one of the ram slots? thats probably why
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Thank you yes at the time I ordered the PC there were almost no AIO options so it came with that 360 one which covers 1 of the RAM slots so I cannot install 8 sticks. I bought another set of 4 sticks recently and added 2 to this threadripper and 2 to my other threadripper so they both have 6 sticks now. I want 8 but both machines have AIOs that interfere. :(
I checked tonight and it looks like now there are some AIOs that don't block the slot so I think I could get a new AIO and run all 8 slots but then I need to look up and see if my MB can still run all 8 at 3200Mhz or if it will drop. Plus the new AIOs might keep it cooler.
I am putting them through a stress test right now rendering a 3Ds max scene to see if they will crash with the new RAM added. So far so good since it wasn't an 8 stick set but rather 2 sets mixed.
 
motqalden said:
Yes exactly. And most systems don't even need both 8 pins but higher end core count motherboards often need the second one if you are gonna push it / OC. That is why despite the message on boot post, you are assumably able to run it.

View attachment 538163



The 3 on the left are all plugs for 8 pin or 6+2 pin PCIE. The two under the 24 pin on the right would be the cpu 8 pin, 4x4. I think on the psu end anyways you can plug either or into those 5 available slots. The cable will only go in one way on the motherboard end and that is also foolproof by the sizing and plug orientation. The main thing if you need to procure a given cable type is that it's corsair type 4 cable and either cpu 4x4 or pcie 6+2 or 8.
Click to expand...
Thank you again. interestingly the PC has been running at high loads during renders without the one cable connected since I bought it...
I'll check the other cable to see if it matches before plugging the disconnected one in.

Can the GPU plug into 3 of those 8 pin ports too? That would mean the GPU uses 3 of the 8 pin ports and the MB uses 2 of the 8 pin (once I connect the detached cable). It might barely have enough 8 pin ports...I'll have to look closer
 
SLP Firehawk said:
Thank you again. interestingly the PC has been running at high loads during renders without the one cable connected since I bought it...
I'll check the other cable to see if it matches before plugging the disconnected one in.

Can the GPU plug into 3 of those 8 pin ports too? That would mean the GPU uses 3 of the 8 pin ports and the MB uses 2 of the 8 pin (once I connect the detached cable). It might barely have enough 8 pin ports...I'll have to look closer
Click to expand...
yes that PSU supports 3x gpu plug and 2x cpu plug at same time.
 
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