powering video card in a new computer

March 12, 2014 8:54 PM

I bought a new computer and realized that the power supply does not have a dedicated six pin cable for my video card. It does, however, have two sata cables coming from it (like this) that are situated in reserve for an extra bay device and also an extra hard drive. Can I use an adapter to sufficient convert them as a power source for a six pin Radeon HD 6850? If so, would it require a converter for both sata connections, or just one?
posted by SpacemanStix to Computers & Internet (17 answers total)

SATA -> PCI-E power adapters don't seem to exist. Are you sure you don't have any 4-pin molex connectors available from your power supply? The standard adapter is molex -> PCI-E.
posted by WasabiFlux at 9:24 PM on March 12, 2014

People say that underpowering your components can wreck stuff. I've never seen this happen, so I can't vouch for its accuracy, but it might be worth some research, at least in your actual power supply capacity (which is lower than what's written the power supply itself) and video card power needs under load.
posted by cnc at 9:39 PM on March 12, 2014

Response by poster: SATA -> PCI-E power adapters don't seem to exist. Are you sure you don't have any 4-pin molex connectors available from your power supply? The standard adapter is molex -> PCI-E.

Yes, I'm certain. No molex adapter. However, I did find this, which I think will solve the problem.

There also exist a single sata to six pin adapter, but I thought that in light of potential underpowering, I'd rather have more power than less. I don't see myself using an extra sata any time soon.
posted by SpacemanStix at 10:00 PM on March 12, 2014

Best answer: While you're at it, you might want to double check the wattage on your power supply to make sure it's even capable of driving your card. Many PSUs that come with new computers don't have the necessary wattage, and the fact that yours doesn't have the 6-pin connector makes me suspect that yours is one of them.
posted by Aleyn at 10:06 PM on March 12, 2014 [3 favorites]

Best answer: Yeah, what is your power supply rated at? I'd expect an HD 6850 to draw between 200 and 250 watts under heavy load.
posted by Justinian at 10:54 PM on March 12, 2014

Best answer: If your PSU doesn't have a connector for this, it is almost certainly the case that it lacks the capacity to support the card, whether or not you can get an adapter for it.

Time to upgrade.
posted by valkyryn at 3:24 AM on March 13, 2014 [1 favorite]

Best answer: What you need is a Power Supply Calculator like this apparently popular one.

Newegg also has one

As does Asus.

Agree with the above, that any PSU old enough to lack this connector is probably also lacking in the juice, and probably isn't long for this world anyway, depending its use of course.
posted by Sunburnt at 6:37 AM on March 13, 2014

Response by poster: Thanks everyone for the good advice. Much appreciated. I'll see if this requires an upgrade to the power supply.
posted by SpacemanStix at 6:50 AM on March 13, 2014

Best answer: From the excellent somethingawful partspicker thread:

13. How much wattage does my PSU need? Can I use my old one?
Wattage is not the most important choice when buying a PSU. The power supply is the only part of your system that can destroy everything else in your computer, so buy a well-constructed unit from a reliable brand. Also, any PSU, even a good brand, should be replaced after ~ 5 years.

We recommend:
- Corsair (but NOT CX/Builder Series models)
- Seasonic
- Antec (Earthwatt series)
- XFX

Other brands may cut corners or give deceptive power ratings. There are other good brands, but it's impossible to keep a comprehensive list. Below are general wattage guidelines. These recommendations only care about your video card - the other components in a system don't vary enough to matter for PSU sizing.

- Onboard video/no PCIe power plug on the video card: 300w
- 1 PCIe power plug on the card (GTX560, Radeon 7770): 400w
- 2 PCIe power plugs on card(GTX760, Radeon 7950): 500w
posted by Sebmojo at 2:45 PM on March 13, 2014 [1 favorite]

Response by poster: Okay, so I have an adequate power supply installed (which I know, as it powered the same card on another similar rig), and it has the six pin power cord. However, the computer boots, but I can't get the card to output to the monitor. The computer recognizes that a video card has been installed, but the monitor itself does not power up as if it is being used. If anyone is still around, do you have any thoughts about this? It's possible that the PCIe slot is not working correctly, but by virtue of the fact that it recognizes the card, I'm thinking that's not the first thing to consider.
posted by SpacemanStix at 9:08 PM on March 13, 2014

Best answer: How are you so certain it's recognizing the card? Just because the fan(s) spin up on the car, or you get a normal POST beep doesn't mean the card is necessarily actually fully powering up.

The first thing i'd do though is pop the CMOS clear jumper on the motherboard and try powering on again with the bios settings wiped.

Then, well, have you tried all the outputs on the card yet? Several cards i've used would only output video on the innermost(IE: closest to the PCI connector) output at first. A lot of newer cards don't seem to care and instantly detect what's up, but a 6850 is just old enough i could see that coming into play.

also try powering the monitor on right when you try and boot the system, it might be falling asleep too quickly or the signal not coming to it long enough to show you what's going on. Which is to say, you might get the VGA BIOS(separate from the system bios, usually just AMD 6850 VERSION BLA BLABLA COPYRIGHT BLA BLA in the upper left corner) which only shows for like one second... and then just nothing, as the motherboard isn't playing nice with it.

Really though, clear the cmos and try the card in another machine before you mess around with anything else.

Another left field one to check, whether the little sleeved conductors inside the 6 pin connector are properly seated inside the molex plug. I mean the one on the power supply cable, not the pins on the card. Sometimes they get popped out a little bit and aren't making contact, so the card can't wake all the way up.

Best of luck, for some reason other than SCSI cards GPUs are like the black hole of desktop troubleshooting most of the time.
posted by emptythought at 4:17 AM on March 14, 2014

Response by poster: Thanks for the feedback. I'm fairly certain that it's detecting the new card, because after installation, when it wasn't detecting, I hooked it back up to the video output from the motherboard, and it said something to the effect of recognizing that a new video card has been installed, so please hook up your monitor to it and restart your computer. This is supposed to direct the user to the installed card, where the computer will then walk through the driver installation on startup. However, on hooking the monitor up to the card directly, there is no signal output at all on restart. Since I can't hook it back up to the onboard video at the same time the card is installed, there's no way to troubleshoot. I've tried turning on the monitor at reboot and no dice. Also, I have a dual monitor display that I've tried between monitors on both card outputs, and nothing.

I think the card is okay, as I just used it on another computer. I suspect that the PCIe slot is okay, as it detects the card. What I'm wondering is if it's about the onboard GPU that intel is putting on some of their chips is conflicting with the card. I've tried disabling it through system properties and then restarting with the card installed, but it still doesn't work. I've read somewhere that Dell machines sometimes need the onboard GPU disabled through the BIOS before installing a graphics card, as it won't always do it automatically on the new GPU installation. I think that's what I'll look into next.
posted by SpacemanStix at 8:56 AM on March 14, 2014

Best answer: Hm... so, your card is detected inside Windows? If you type "device manager" into the start screen/menu to get to the device manager control panel, do you see your card under the "Display adapters" section (and not something like "Standard VGA Adapter")? Does it have any warning/errors on it? If you see your card without errors, that doesn't sound like a BIOS issue, and you should be able to use the outputs on the card. You could try disabling onboard video in the BIOS and see if that helps, but make sure you know how to reset your BIOS via the CMOS reset jumper on the motherboard just in case that doesn't work.
posted by Aleyn at 9:05 PM on March 14, 2014

Response by poster: The reason I think it's detected is because the video connection built into the tower works while the card is in the slot, but only to tell me one thing: move the monitor cable from the tower to the card that you are trying to install. It won't let me access the computer another way if the card is in the slot.

So what this means is that I can't do anything on the computer to investigate why I'm not getting a signal from the video card, because the computer is only letting me get access through the video card.

I went through all of the bios options, but it doesn't have a setting to disable the on-board video as I was hoping. I was able to disable it through device options when the card isn't installed, and then try the card in the slot again. But still nothing.

One thought is to perhaps activate the bios setting that allows you to use the on-board video to display a third monitor apart from the video card. Maybe I can hook up a monitor to the video connection in the tower while the card is installed, and get access to the device manager that way.
posted by SpacemanStix at 9:49 PM on March 14, 2014

Response by poster: If anyone is still reading, I was able to solve the problem. It ends up that this new version of windows (8.1) didn't find a driver compatibility with the card (which seems to not be a unique problem that only I had, per some online discussions), and since I couldn't work on the card with it actually being installed, I wasn't able to navigate within to find a solution. I heard, however, that the on-board graphic adapter can sometimes power another monitor while a video card is installed, so I went in and activated it through the bios, and then was able to use another monitor through the motherboard connection while the video card was in the slot to discern the problem. It ends up that windows was assigning it a generic driver designation but not letting it operate, so I downloaded the most recent ATI driver, and it then recognized the card. So, all is now well with the world.

Thanks for all the help and good suggestions.
posted by SpacemanStix at 10:22 PM on March 15, 2014 [2 favorites]

Best answer: Oh. I thought you had already tried that; Windows has supported using multiple graphics adapters for years, so yes, in the future, you can totally do this with basically no negative consequences. Glad to hear you were able to figure it out! :)
posted by Aleyn at 3:38 PM on March 17, 2014

Response by poster: What was weird to me is that it didn't default to using both adapters, and that I had to access this option through the bios. It was a really inconvenient process if your computer happens to not recognize the video card or driver needed. I'm still not entirely sure why the Windows default driver didn't allow me to at least see something. Oh well, I'm just happy it's working.
posted by SpacemanStix at 1:10 PM on March 19, 2014