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Graphics Would this work or give me a GPU error?

Discussion in 'Hardware' started by Vault-Tec, 22 Feb 2020.

  1. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    Guys. So I bought an X51 that needs repair, right.

    [​IMG]

    OK, so the unit comes with the 240w power brick used by Dell, and not the 330 one you could spec. They're about £150. However I have had an idea sought of concocted from another idea I saw. Only I could execute it better and more professionally.

    Right, so some guy has whatever founders sized card he wants running in his rig (780TI classy, IIRC) and he did it by basically hot wiring a 800w PSU to power it.

    Right, I checked my CPU (I5 3330) and it has onboard graphics and a HDMI on the back plate.

    Now, what about this for an idea.

    Cut into the back of the case and fit two 8 pin connectors. Then inside run this to 2 8 pin GPU cables. I can fix a PSU to the back of my bedroom unit and run two nicely braided extended cables out.

    If I want games in the bedroom I connect to the 600w Cougar PSU. If I don't I disconnect the two 8 pins or whatever I need for a good GPU and roll back to the IGP.

    However, what makes me concerned is *IF* turning it on with the GPU in would stop it booting at all because it knows there's a PCIE card plugged in with no external power.

    Again, a confusing subject because once again no one has really tried it but I just wondered what you guys reckon.

    It doesn't matter if the idea does not work, because I have two other uses for this thing if I can't turn it into a gamer.

    Thanks !
     
  2. bawjaws

    bawjaws Well-Known Member

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    I'm pretty sure that if you have a GPU installed in the PCI E slot and don't have sufficient power hooked up to it, your PC won't boot.

    Happened to me recently when one of my power cables got knocked loose from my 2070: the PC wouldn't boot, with a message about the GPU power needing to be connected. An added bonus was that the fans on my 2070 run at 100% when you don't have the power hooked up.
     
  3. Anfield

    Anfield Well-Known Member

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    99.9% chance that the GPU would send an error to the system and prevent booting.
     
  4. Corky42

    Corky42 Where's walle?

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    I'd test how the system deals with a card not having external power first, on a old system i had it was fine until i tried running something that needed 3D but going on what bawjaws says some system won't post, i guess newer systems or different systems deal with it differently.
     
  5. wolfticket

    wolfticket Downwind from the bloodhounds

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    I would assume it would either post with the card and then fail when/if it tried to use more power than PCI E could supply, or more likely as above it would fail on boot because a self check detected a necessary power connector missing.

    Either way I very much doubt the system would ignore an external GPU just because the power is disconnected.
     
  6. Anfield

    Anfield Well-Known Member

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    Indeed, the power provided via pci-e is enough for the GPU to transmit an error message to the system.
    So unless you had a way to shut off the pci-e power or prevent the GPU from doing any self diagnostics before boot you'd be stuffed.
     
  7. wolfticket

    wolfticket Downwind from the bloodhounds

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    I guess you could add a rather under-powered PCI-E connector from the standard PSU (probably sata>pci-e) and run the pci-e GPU with a low power profile (i.e. heavily underclocked) so the machine boots and runs from the 240W brick with the new GPU but without overloading the PSU for general use (this would obviously work better with more modern GPUs that have low idle/near idle power usage).

    ...Then add a double-pole, double-throw switch in order interrupt the added pci-e connector so you can (while the system is off) switch to using your external supply, and then change the power profile for gaming when it is connected.

    Probably a terrible idea that will burn your house down though :worried::grin:
     
  8. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    I know all of this.

    Like, how some GPUs will put a message up on screen to tell you about the power.

    What I wanted to know was if the onboard GPU would still work with the monitor plugged into that, with a pcie GPU without any power in the rig.

    Oh the joys oh thinking esoteric, lol. I guess I'm a have to suck it and see :D
     
  9. GeorgeK

    GeorgeK Swinging the banhammer Super Moderator

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    It might do - you might be able to go into the BIOS to change the device you want it to use. Problem is that if it's trying to use the discrete GPU and it's not powered then you might not be able to see the BIOS screen in the first place... I suppose it's worth a try but I'd be very surprised if you get it to work reliably
     
  10. Anfield

    Anfield Well-Known Member

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    But that is the point, if the iGPU works is irrelevant because the PC isn't going to ignore the "I don't feel so good" coming from the dGPU.

    Now if you set it in the bios to only use the iGPU it *might* ignore the "I don't feel so good" from the dGPU, even if that worked you'd be fiddling around on every boot depending on the status of the external PSU.
     
  11. bawjaws

    bawjaws Well-Known Member

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    Ah, gotcha. I think it'll probably depend on your motherboard, really. You should be able to select whether you want to use the integrated or discrete GPU in the UEFI but I've just tried this and board won't boot, regardless of which GPU is selected, if there's not enough juice going to the discrete GPU. YMMV, of course, so you might just need to suck it and see.
     
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  12. nimbu

    nimbu Well-Known Member

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    Hmm,

    I can remember way back when getting a warning that the graphics card wasn't getting enough juice when I forgot to plug in the GPU power connectors.

    Windows itself booted fine though and I was able to use the desktop fine. Iirc it was either my GTX 980 or my 7970

    I think the trouble you may face is how to pipe the output from the discreet card through the igpu hdmi.

    Assumptions:

    Your rig behaves like mine
    You can't pipe the discreet you through the igpu

    You add a second flip switch that will short the two connectors on the ATX PSU to power the discrete gpu.

    When you want to game from cold you flip that switch first, then the regular power on switch.

    You might want to set some really low after burner profiles to keep the card power usage right down.

    If it only works that the dgpu must have full power at boot, you could use a pi with some relays. I.e,

    The case switch is wired to pi gpo, when you press the button, one relay does the momentary switch to turn in the mobo, the second does the permanent short if the required connections of the external PSU. Maybe it could be a pi zero which might be powerable via USB standby from the mobo.

    Got me thinking!
     
  13. nimbu

    nimbu Well-Known Member

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    Ok some Google fu. The x51 R1 and R2 boards appear to have ATX connectors.

    I'm assuming the power brick plugs into a connector on the I/o shield?

    If so ditch that and grab a 150 / 160 picu PSU, I think the brick can be used with that. Also I've seen these things that allow you to use two PSUs in one system. Creates a bridge.

    Final option and not for the brave. Ditch the dell PSU converter and convert and ATX psu to an external brick. Fit some PSU extender cables to the back of the rig and then the external PSU to those.

    Again with all that effort,maybe just grave a Silverstone raven...
     
  14. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    Let me explain more.

    The Dell uses a 19v 240w brick into the pc. Where it gets alloted to the hardware. Board is a stock itx sort of affair.

    I know for 100% you can definitely power GPUs on a separate psu. Back when I bought an old phenom, two 3870x2s and a 8800 ultra. I powered the 8800 ultra from a stand alone 450w PSU and the rest from the rigs 1000w. You just short the 24 pin to turn on first and then boot the rig. I even have pics of it somewhere lol.

    As I said, I know that if you don't power a GPU and fire it up either nothing happens or you get an on screen error telling you. However that happens only when the monitor is plugged into the GPU with no power and that error is generated by the GPU itself, not the onboard.

    I'm wondering what will happen with the onboard plugged into the monitor.

    I do have an old Quadro I can use as a test subject, but no access to the rig for two weeks.

    I can't use a powerful modern GPU any way, as they are all UEFI only now so I'm capped at 10 series Nvidia or 300? Series AMD.

    TBH I'm leaning more toward using it as a new Nas with no GPU and a 1gb internet card in the pcie slot. As I type this my old SMB1 Nas is vibrating loudly as the shell is old lol.

    So aye I'll probably end up being sensible with it and not trying to get it gaming now.

    [​IMG]

    There we go. lol. Talking of lol, it never takes me long to find the pic because I titled it LOL
     
    Last edited: 25 Feb 2020
  15. adidan

    adidan Guesswork is still work

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    I know that feeling, I sometimes wish I could rig up an external PSU to give myself a bit of extra juice.
     
  16. Anfield

    Anfield Well-Known Member

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    The problem is that even if it works you would then have to fiddle around to get the dGPU working whenever you want to use it.

    Honestly, if you want to put a dGPU in a case that can't accommodate a proper PSU I'd just use one single PSU externally and secure it to the case with some straps rather than faffing about with two PSUs, iGPU etc
     
  17. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    TBH looking at the case and where the dvd drive goes this may even fit in there...

    https://www.amazon.co.uk/dp/B07BVTT...olid=1GDMFRLXSU6WK&psc=1&ref_=lv_ov_lig_dp_it

    If not it's a NAS 100%
     
  18. Anfield

    Anfield Well-Known Member

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    Optical drives are 4.2cm thick, that PSU is 4.05cm, so that should work space wise.
     
  19. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    It's quite big for an itx rig tbh. It would be I guess, the design is very old now.

    It's a slot load drive, but there still seems to be quite a bit of room there.
     

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