Turn on GPU before Mainboard?

Sirvaude

n00b
Joined
Apr 9, 2016
Messages
1
Hi there, I have a doubt.

Can I give 12v to a GPU (turn it on) before I turn on the mainboard?

I have a Gigabyte 7970, and a MSI Z77A-GD55, I also have a generic "500 Watt" PSU to supply the mainboard, and a HP DPS-1200FB PSU; I'm wondering if I can use it to supply only the GPU.

Assuming that I can supply the GPU with that HP PSU; Due those PSUs works separately, do I need to turn them on at the same time or can I turn on the HP before the generic one?

I need to solve THAT doubt. AFAIK, I can use a relay of 5V or 12V connected to the generic psu and so, it will turn on it at the moment I turn on the mainboard... but before I do anything and burn something I need to know if I'm right or how should I do it.

Thanks in advance.

--> EDIT: Please excuse me if this isn't the right subforum, I'm new.
 

dethklokworkorange

Limp Gawd
Joined
Jul 23, 2013
Messages
176
I'd say you technically can, but probably shouldn't. At the very least I'd first check to see the (seemingly sketchy) gpu psu was still supplying the right voltage without the 24 pin connector actually consuming any power. And back up the hard drive. And make sure my insurance was current.
 

primetime

Supreme [H]ardness
Joined
Aug 17, 2005
Messages
6,623
Hi there, I have a doubt.

Can I give 12v to a GPU (turn it on) before I turn on the mainboard?

I have a Gigabyte 7970, and a MSI Z77A-GD55, I also have a generic "500 Watt" PSU to supply the mainboard, and a HP DPS-1200FB PSU; I'm wondering if I can use it to supply only the GPU.

Assuming that I can supply the GPU with that HP PSU; Due those PSUs works separately, do I need to turn them on at the same time or can I turn on the HP before the generic one?

I need to solve THAT doubt. AFAIK, I can use a relay of 5V or 12V connected to the generic psu and so, it will turn on it at the moment I turn on the mainboard... but before I do anything and burn something I need to know if I'm right or how should I do it.

Thanks in advance.

--> EDIT: Please excuse me if this isn't the right subforum, I'm new.
First thing you need to do is throw that generic power supply in the trash before it burns up whatever its hooked to! Or play with fire lol its your choice. They do make adapters for adding additional power supply's to prebuilt pcs with shitty power supplys but you run into all kinds of issues with where its going to mount and then theres the cooling issue for the card your trying to use. Its all a moot point if all you have is a generic power supply and on top of that you need to buy the part for adding the additional supply. If you dont have any money at all the project should stop now. (at least you have a working pc)
 
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RazorWind

2[H]4U
Joined
Feb 11, 2001
Messages
3,713
I'm not going to tell you that you can't use a cheap power supply successfully, because I've done it for years. At least in my experience, when power supplies fail, they just quit working. No fire or dead components or anything like that.

With that out of the way, this doesn't seem like the best way to go about this. Why not just get one good power supply that can power the whole system, so you don't have to ghetto rig two power supplies? You shouldn't need a terribly expensive one - most of Corsair's in the 600-700 watt range are perfectly adequate, if not flashy, and reasonably priced.

I'm willing to be convinced that this is a good idea for reasons I haven't thought of, but currently, it just seems like you're doing things the hard way.
 

Brian_B

2[H]4U
Joined
Mar 23, 2012
Messages
3,356
I'm not going to tell you that you can't use a cheap power supply successfully, because I've done it for years. At least in my experience, when power supplies fail, they just quit working. No fire or dead components or anything like that.
You've been extraordinarily lucky. RAM and motherboards are common victims - GPUs and hard drives are not uncommon. I've never had a CPU go out with a PSU. Often, what happens, is you say "Oh the motherboard died" - so you swap out the motherboard, and it works great. Then 2-3 weeks later, the PSU dies. PSU was probably what killed that first motherboard, and you'll be lucky if it doesn't take something else with it when it does finally let the magic smoke out.

That being said, I do agree - if someone wants to run cheap stuff, more power and good luck to them. I've done it myself when I was younger, and fortunately now I'm in a position where I don't have to. It just seems to be worthwhile insurance to get a better PSU in the first place, especially if you are running expensive video cards.
 

primetime

Supreme [H]ardness
Joined
Aug 17, 2005
Messages
6,623
lol i talk from personal experience. When i first started out i sold a pc with a generic power supply and of course i gave them my word it would last. Cost me about 400 bucks to build them a new pc after the one i sold got everything burned up from the dam power supply just 30 days later. Since then generic power supplys get thrown in the trash. lol i learned the hard way -like everything:(
 

Darakian

Supreme [H]ardness
Joined
Apr 12, 2004
Messages
4,699
Can I ask why? Or how even? I'm pretty sure that supplying power from an alternate psu to the connectors won't actually start the card up. I'm pretty sure the boot up comes from the pci-e power. That all said please report back on how this goes.
 
Joined
Mar 29, 2012
Messages
727
It might be possible to use another PSU for the 8-pin power connectors on the GPU, but I don't think that would turn the card on. That would only supply some of the card's power, though... a lot of it would still be coming off the PCI-E bus itself. Chances are that it wouldn't even start drawing on that 8-pin power connection much until you started up a game. A lot of cards don't even need additional power to run.

The only reasonable way to turn the card on before the mainboard would probably be to have it in some kind of external enclosure, and then it would have to have its own BIOS and a way to transmit data to the computer. It would be a mess.

I don't know if there's any real danger in doing this, but I'd say it's probably better to turn the mainboard on first, and then turn the 8-pin plug on a few seconds later. Turning the card's 8-pin on first probably won't do anything, but if it did do anything, it would likely be bad.
 
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