Desperate dad building first PC for son. PC won't turn on if graphics card is connected to PSU
Posted by silasgoldeanII@reddit | buildapc | View on Reddit | 66 comments
We have a new build for my son. GeForce RTX 4070 graphics card, Corsair RM750x psu, AMD Ryzensets 5 7600X Processor. We couldn't get any power, but then when I unplugged the graphics card's connection to the PSU we can. Can anyone explain what's going on here? We checked and thought that the PSU should be able to make all this work.
Is it something to do with cables? We have the 8 pin cable that came with the graphics card, so is my challenge now to make sure that I fit two other cables into this and connect them to the PSU? I have one PCIe cable that has 8 holes each end and one that has 8 one end and 6 the other. Is this the problem?
Thank you!
Rubbertutti@reddit
Check power requirements of the 4070.
Normally when you have power issues you un plug everything from component to psu inspect and replug. Look for any deformed pins on the cable and make sure you are using the cables that came with the psu, not cables from another psu they are not all pinned the same. If the psu is used then look on line for a pin out and do a continuity check on all pins. Think back in the days of the cartridge consoles, when you had to blow down the connector.
Except blowing was a sacrifice to the cartridge gods, pulling the cartridge out and putting it back in was sufficient.
HTLP@reddit
Post a picture of the cables and how you are connecting them.
silasgoldeanII@reddit (OP)
I've updated the OP to show what cables I have available to me. Does that help?
E3FxGaming@reddit
Take a look here at the Corsair website that depicts which cables come with the RM 750X.
You want to use the second cable from the left in the bottom row of cables.
Plug one end into the PSU socket labeled "12V-2X6" (also shown on the Corsair website - on the PSU it's the 3rd socket from the left in the top row).
Plug the other end into the GPU (only has one socket).
Don't use any splitting adapters - your PSU natively supports this 12VHPWR standard.
Make sure the cable is seated correctly on both ends into the respective sockets. Maybe consult a video for this, it's really important.
Gregardless@reddit
This is the way.
Gregardless@reddit
The most helpful comment so far
AstarothSquirrel@reddit
You should have more than one pcie cable from the psu. Normally, if you have a 6pin pcie, it will have an addition 2pin that can attach to the side to make it an 8. You have to connect two separate 8's to the y shaped adapter (not the daisy chained pcie for older gpus) the end set up should be: power to motherboard; power to cpu; two pcie (8 pin and 6+2 pin) going into y shaped 12vhpwr cable that goes into gpu. pay attention to the shapes of the pins and don't force the wrong shapes into each other like one user did. the 6+2 should slide together so that you know which way round they go.
silasgoldeanII@reddit (OP)
OK I think this might be it. So the 8 and 8 and the 6 and 2 into the y thing? Sorry am just out walking the dog, will try.
AstarothSquirrel@reddit
Yes. PSUs often come with a pcie with two 8pin plugs daisy chained on the same cable, only use one of those 8 pins on the modern gpus. basically, the new gpus need to draw power from two cables from the psu, not one cable with two plugs. So you have to use another pcie cable (The new GPUs are a little power hungry) But, with this extra juice going into the gpu, it's important to ensure that the plugs are plugged in correctly because, whilst the cables can handle the current, any stress on the cable can cause weak connectivity points in the connector increasing risk of heat and fire so make sure your cables have gentle curves and not tight bends.
silasgoldeanII@reddit (OP)
It's working, I hadn't realised the 6+2 cables would snap in like that so was using the 8 pin which weren't. Thank you.
AstarothSquirrel@reddit
No problem, hope you have a great day.
Asstaroth@reddit
Did you connect the monitor to the gpu or is it still plugged into the motherboard?
silasgoldeanII@reddit (OP)
Gpu but this is happening independently of the monitor, I've taken it back to the main table and it's happening without the monitor being involved.
Asstaroth@reddit
Just to confirm, when the GPU is plugged in there’s zero power to the motherboard - no LEDs and cpu cooler fan not spinning?
You mentioned you have one pcie cable that has 8 holes on each end - can you double check if it is marked pcie or cpu
The other cables (should be more than one) with 6+2 on one end should be the pcie cable that goes into the gpu. Have you tried plugging these in a different port in the PSU side? There should be more than one place on the PSU itself marked “pcie”
You also mentioned there is an 8 pin cable that came with the GPU - can you post the exact model of graphics card you got?
silasgoldeanII@reddit (OP)
Thanks. It's a Zotac GEFORCE RTX 4070 SUPER TWIN EDGE 12GB.
I have edited op to include cable pics. I suspect I've been using the wrong one. The one with 8 each end says cpu.
Asstaroth@reddit
Try this:
PSU > 2 of the pcie cables (the ones with 6&2) > the 16 pin cable that came with the psu > PSU
silasgoldeanII@reddit (OP)
That's it. Thank you.
Asstaroth@reddit
Congrats - bet your kid is happy now lol
silasgoldeanII@reddit (OP)
We still need to install windows and who knows what else will go wrong but at least it turns on now. Was very stressful as hasn't been a quick process haha. Thanks so much.
Asstaroth@reddit
You’re welcome. Yeah it can be stressful for sure but once you start playing it’s the best feeling knowing that you built it. Would also be a real good bonding experience for your son I imagine, and it’s gonna mean a whole lot more to him than a prebuilt
kingwhocares@reddit
What's your power supply and its rated watts?
redilred@reddit
Not a great response, but I had this exact same issue when my 980Ti GPU died. Took me far too long to figure out everything worked fine when the GPU wasn't mounted or connected. I'd honestly look into an RMA for that GPU
risforpirate@reddit
Hope you were able to get this fixed!
Mrcod1997@reddit
This is gonna sound obvious, but is the power supply turned on and do you have the power button on the case actually hooked to the motherboard?
silasgoldeanII@reddit (OP)
Yes, it works when we don't have the graph is card connected to the psu but not when we do.
DepartureActual308@reddit
Then your problem is related to the power cable that connects to you graphic card. Share a picture with us.
silasgoldeanII@reddit (OP)
I've out some links in op now. Does this look like the right combinations of cables?
TheMooseontheLoose@reddit
Can you take pictures of the connections?
silasgoldeanII@reddit (OP)
I've put pics of the cables I have in the post. Thanks. I have disconnected it all now but does it look like I have the right things? Or is there another cable I ought to have used?
kikimaru024@reddit
silasgoldeanII@reddit (OP)
Sorry what do you mean connect monitor graphics card? This is all independent of a monitor. Or is that not what you mean?
DepartureActual308@reddit
All motherboards have a hdmi connector for CPU that have integrated graphic cards. But in your case, if you have a dedicated graphic card, you must make sure that the monitor cable goes into the hdmi slot of the graphic card.
silasgoldeanII@reddit (OP)
Oh yes we did, but this is happening when we aren't even using a monitor.
nohardRnohardfeelins@reddit
100% it's #1
thepohcv@reddit
Agreed. Came here to put my money on the first of these comments I saw lol.
0NiceMarmot@reddit
GPUs don’t come with cables. Cables are specific to the PSU since the PSU side is not standard. Pin outs are different between brands and even models. Also they’re directional so pay attention to the labeling.
CJLOLZ@reddit
The pins on the device end are pretty standard (how would you ensure your components and PSU are compatible)
Most, if not all cables are keyed in some way to prevent power going where it's not supposed to.
GPUs might not come with cables, but they may come with adapters if their connector is uncommon or new (see 4090s coming with a 12VHPWR adapter)
silasgoldeanII@reddit (OP)
I've attached pics in op. Do these look correct?
jasovanooo@reddit
make sure you have the pcie power cables correctly into the adapter
Also make sure both are actually pcie and not the atx12v (it will fit if pushed but has a different pin out)
on an rm 750 the correct ones are usually 8 pin at psu end and 2x 6+2 pins on the gpu/adapter....the wrong one is either an 8 both ends or a 4+4 on the board end
silasgoldeanII@reddit (OP)
I've updated OP with pics of what I have. Should these do the job? Or have I put the right cable somewhere else?
alex_theman@reddit
When the system wasn't booting, were you using the power adapter/cable that came with the GPU or was the power supply's PCIe power cable plugged in directly?
silasgoldeanII@reddit (OP)
The one that came with the gpu, it splits out into two and we then attached that to one (then two) of the cables that came with the psu.
kikimaru024@reddit
Ah shit, I think you have the PCIe connected the wrong way around!
From the split-cord PCIe cable:
Hope you didn't destroy it!
MrMusAddict@reddit
If the GPU had a 1x8 pin connector, then it wouldn't come with an adapter. Absolutely sounds like OP's card is one of the 4070's with a 12+4 cable which comes with an adapter. They just need to use the one that comes with the PSU instead.
silasgoldeanII@reddit (OP)
Pics in OP now. Thank you.
silasgoldeanII@reddit (OP)
I've updated OP with links to cables available. Should it work with these?
nigirizushi@reddit
I don't think you're thinking of the right cable.
It should be a PCIe 8 pin on the GPU side, and two 2x3 molex on the PSU side.
kikimaru024@reddit
What the absolute FUCK are you talking about?
OP's Corsair PSU
Note how it uses 8-pin connectors for "6+2 PCIe & 4+4 CPU"?
nigirizushi@reddit
Who the fuck is talking about the PSU cable? I'm talking about the adapter that comes with the 4070 that OP was talking about.
Little-Equinox@reddit
1 thing to know about the CPU, it sometimes takes longer to dp RAM training, if it's stuck still after half an hour, turn off the PC completely(turn off PSU), take-out the CMOS, hold the power button for like 10 to 20 seconds, put the CMOS back in and try again, if it still doesn't work, try another PCIe slot.
Don't worry, the 4060 and RX 7600XT work fine on 8x slots as that's all they have.
And also keep in mind, a mistake I see a lot with 1st time builders, don't over tighten the CPU cooler, it can make the PC misbehave and/or break.
MrMusAddict@reddit
The RM750x should come with a native 12+4 cable for GPUs. I would try using that one, and make sure the GPU is fully seated, and so is the power cable.
And when you say you're not getting power, do you mean at all? Or do the lights and fans come on but just no signal?
kikimaru024@reddit
Most RTX 4070 models uses 1x 8-pin PCIe connector.
MrMusAddict@reddit
More likely to not have the 12+4 for 4070, true. But also the OP said the connector is split into 2, so that sounds more like a 12+4.
alex_theman@reddit
You should use the PCIe cable(s) that came with the power supply and bypass the adapter provided with the GPU. The only reason to use that adapter is if the power supply doesn't have enough PCIe connectors. In this case, use an 8 pin PCIe cable provided with the power supply.
Commander_in_Beef@reddit
You aren't pigtailing just one cord from the psu correct? You have 2 separate cords going into the GPU adapter, right? Also if you PSU came with a 12+4 cable for the gpu just use that. It looks like this.
https://www.amazon.com/Fasgear-Power-Cable-Sleeved-Combs/dp/B0BF4C67GP?th=1
Naerven@reddit
In order to try and simplify this what exactl GPU do you have? We know it's a rtx4070, but which exact one?
CJLOLZ@reddit
Power draw is negligible between manufacturers. An OC might pull 5-10% more at load, but likely not at boot.
StableEmbarrassed445@reddit
Hi Friend! Don’t know if you were able to get things up and going yet BUT one thing that definitely stands out to me is the 750 Watt PSU… I am thinking that you might not have enough power for your build.
The more fans, rgb, ram, storage, basically any additional device, the more watts you need. Especially with that 4070 which easily eats above 400 watts depending on gameplay.
From there, ensure that you have your HDMI or DP Cable to the GPU Directly, not the Motherboard.
As well as ensure you have properly configured the PSU cables to the motherboard and visa versa.
In-regards to the 8 Pin that was Provided ~ Always utilize the provided cabling as manufacturers have specific standards to their products in terms of power transfer etc.
Mrcod1997@reddit
750 is plenty
StableEmbarrassed445@reddit
Should be for sure, but if OP is running a RGB/Fan/Storage Frenzy you could be limiting not only the performance but the power distribution of your device.
Mrcod1997@reddit
There are people that run much more power hungry stuff on a 750 wat. Besides, it would still power on, it just wouldn't be able to sustain a full load.
StableEmbarrassed445@reddit
Good point. It would still power on then with some systems not achieving their desired capacity
sociableturtle@reddit
750W is totally fine, and the 4070 only draws ~200-250W max. I agree about double checking the video cable is in the GPU instead of the motherboard’s built in display ports.
StableEmbarrassed445@reddit
Agreed, should be absolutely fine. Some cases with RGB Frenzies/Storage always have me double check
WizardMoose@reddit
One thing to note, you got the right kind of PSU. Compatibility concerns are off the table, you did fine. We are going to need a picture/video of how your setup is currently down. It will be hard to film/take pics of, but give a break down of the plugs that are going into the card, where they go exactly.
bunkermunken@reddit
Are you saying that the card has 3x8 connectors for power but you only used 1?