Can I use integrated graphics alongside a GPU?

[mdettweiler]

A few days ago, a friend of mine here (Gary, a.k.a. gd_barnes) bought an nVidia GTX 460 graphics card for use in various crunching applications related to k*b^n+-1 numbers. (Currently a CUDA sieving application exists for these numbers, and we're hoping to see a primality testing program in the near future.) He's not particularly savvy with these things so the idea is that I can log in via SSH and operate the GPU.

The computer he put it in is an Intel Q6600-based system running 64-bit Ubuntu 8.04. It's got your run-of-the-mill Intel integrated graphics chipset on which the monitor was running until now. Since crunching on a GPU slows the graphics to unusability in many cases, we were hoping to keep using the integrated graphics to run the monitor even with the GPU installed.

However, when Gary put the GPU in the computer and started it up (with the monitor plugged into the integrated VGA port), the monitor remained blank. The system is reachable via SSH (and via tightvnc which uses its own desktop session on Linux--vino for the console session doesn't work since it requires the user to be logged in), and for now he's operating it via tightvnc. (It's one of a farm of 10 machines used exclusively for crunching, so this isn't inconveniencing any "real" work.)

At this time we can't try plugging the monitor into the GPU since that would require a DVI-to-VGA adapter (which Gary doesn't have, though he's going to buy one in a couple of days). While that would probably work, ideally we'd prefer to have the monitor run off the integrated graphics. I tried all sorts of /etc/X11/xorg.conf modifications but those only succeeded in messing things up further.

Is it even possible to run the monitor off the integrated graphics with a GPU installed? I'm guessing it probably is (how hard can it really be?); can any of you GPU gurus out there who have had more experience with this stuff tell me how it's done?

Thanks,
Max

[xilman]

Originally Posted by mdettweiler

A few days ago, a friend of mine here (Gary, a.k.a. gd_barnes) bought an nVidia GTX 460 graphics card for use in various crunching applications related to k*b^n+-1 numbers. (Currently a CUDA sieving application exists for these numbers, and we're hoping to see a primality testing program in the near future.) He's not particularly savvy with these things so the idea is that I can log in via SSH and operate the GPU.

The computer he put it in is an Intel Q6600-based system running 64-bit Ubuntu 8.04. It's got your run-of-the-mill Intel integrated graphics chipset on which the monitor was running until now. Since crunching on a GPU slows the graphics to unusability in many cases, we were hoping to keep using the integrated graphics to run the monitor even with the GPU installed.

However, when Gary put the GPU in the computer and started it up (with the monitor plugged into the integrated VGA port), the monitor remained blank. The system is reachable via SSH (and via tightvnc which uses its own desktop session on Linux--vino for the console session doesn't work since it requires the user to be logged in), and for now he's operating it via tightvnc. (It's one of a farm of 10 machines used exclusively for crunching, so this isn't inconveniencing any "real" work.)

At this time we can't try plugging the monitor into the GPU since that would require a DVI-to-VGA adapter (which Gary doesn't have, though he's going to buy one in a couple of days). While that would probably work, ideally we'd prefer to have the monitor run off the integrated graphics. I tried all sorts of /etc/X11/xorg.conf modifications but those only succeeded in messing things up further.

Is it even possible to run the monitor off the integrated graphics with a GPU installed? I'm guessing it probably is (how hard can it really be?); can any of you GPU gurus out there who have had more experience with this stuff tell me how it's done?

Thanks,
Max

Sorry I can't help much but I can confirm that you're seeing a common problem. I tried something similar and saw exactly the same as you. The BIOS on my machine insisted on disabling the integrated graphics whenever a card was added. You might be able to persuade your BIOS to behave itself but I failed with mine.

One possible approach might be to buy a cheap and cheerful card (nVidia by preference to avoid drivers fighting amongst themselves) and run the display off that. The 460 would then be a pure computation engine. If you go this route, it would probably be a good idea to see if you can borrow a card to see whether the scheme works before spending yet more money.

Paul

[schickel]

Originally Posted by mdettweiler

Is it even possible to run the monitor off the integrated graphics with a GPU installed? I'm guessing it probably is (how hard can it really be?); can any of you GPU gurus out there who have had more experience with this stuff tell me how it's done?

Thanks,
Max

Can't say that I'm a GPU guru, but I can speculate with the best of 'em.

My first guess would be that the BIOS needs to be reconfigured. Most BIOSes (BIOS's?) have a setting to tell the PC how to initialize the graphics on power up. If it's set to AUTO, it probably detects the GPU in the slot and initializes that one on start up and ignores the integrated VGA.

One thing to check would be if there is any activity on the VGA output at all while POST is going on. If so, you could try getting in to the BIOS setup on power up and change the grpahics settings. If you can't get to the BIOS with the GPU in place, try taking the GPU out, boot to the BIOS setup and change the configuration, then put the GPU back in.

If the OS is plug-n-play and has recent enough drivers, you might be able to tell the BIOS to initialize only the VGA on power up and let the OS detect the GPU and bring it online.

I am strictly a Windows guy, so I can't speak for Linux, but after you get the BIOS set, Windows boots up with the graphics adapter active at boot up as the primary and any other grpahic adapter(s) available as secondary (tertiary) ....

(And I see that xilman has beat me to the punch with one point...and a good idea if you can't get the BIOS to co-operate.)

[axn]

Originally Posted by schickel

My first guess would be that the BIOS needs to be reconfigured. Most BIOSes (BIOS's?) have a setting to tell the PC how to initialize the graphics on power up. If it's set to AUTO, it probably detects the GPU in the slot and initializes that one on start up and ignores the integrated VGA.

Having recently done a similar exercise, I will add my vote for this. I had to go to BIOS and ask it to use the Onboard card as the primary, before it would recognize it. I am guessing that most bioses will automatically disable IGP if a discrete card is added, so you'll have to go back and explicitly enable them.

[mdettweiler]

Thanks for the hints guys--that sounds like it should do the trick quite nicely. I'm wondering though, will the BIOS even display the option to change which graphics is powered on when the GPU is out (so that the monitor works for the BIOS configuration)? Most BIOSes I've seen only display options related to a component if that component exists. If that's the case here, then Gary will need to buy the DVI-to-VGA adapter at least to configure the BIOS.

Also, a family member of mine does have a nearly identical computer (same mobo--I built it around the same time I picked out the parts for Gary's ), so if I can get access to that I'll try doing a "dry run" in the BIOS. That computer has no GPU, so it will simulate what Gary's would be like with the GPU removed.

[henryzz]

Strikes me as a question worth asking at a dedicated hardware forum or maybe at a GPU computing forum like F&H.
Might do that myself if no one has an account anywhere.

[TimSorbet]

Originally Posted by mdettweiler

Thanks for the hints guys--that sounds like it should do the trick quite nicely. I'm wondering though, will the BIOS even display the option to change which graphics is powered on when the GPU is out (so that the monitor works for the BIOS configuration)? Most BIOSes I've seen only display options related to a component if that component exists.

That would depend entirely on the BIOS, of course, but I'd say there's a decent chance it'll give you the option. Definitely worth checking out.
So in all of his computer stuff, Gary doesn't have any DVI-VGA adapters? How odd...have they stopped including those things with GPUs and monitors now? Seems like every time I'd buy something related to video, it had one or two of those little things included.

[schickel]

Originally Posted by mdettweiler

Thanks for the hints guys--that sounds like it should do the trick quite nicely. I'm wondering though, will the BIOS even display the option to change which graphics is powered on when the GPU is out (so that the monitor works for the BIOS configuration)? Most BIOSes I've seen only display options related to a component if that component exists. If that's the case here, then Gary will need to buy the DVI-to-VGA adapter at least to configure the BIOS.

Looks like it really does depend on the BIOS. This system I'm on right now is a Dell Optiplex. The BIOS has a setting for Video, under that there's two choices: Auto and Onboard. The option is configurable even with just the onboard available. According to the help text, Auto sets the primary adapter as onboard unless there's a graphics card available, in which case the add-on gets primary status. Onboard means set the onboard as primary, even if there's an add-on GPU available.

[mdettweiler]

Originally Posted by Mini-Geek

So in all of his computer stuff, Gary doesn't have any DVI-VGA adapters? How odd...have they stopped including those things with GPUs and monitors now? Seems like every time I'd buy something related to video, it had one or two of those little things included.

Say, you're right...looking at the Newegg picture of the graphics card box contents, one of those thingies in there should be a DVI-VGA adapter. I'll drop Gary a line to let him know.

[schickel]

Originally Posted by Mini-Geek

So in all of his computer stuff, Gary doesn't have any DVI-VGA adapters? How odd...have they stopped including those things with GPUs and monitors now? Seems like every time I'd buy something related to video, it had one or two of those little things included.

Why should they include a 50¢ part free when they can sell it to you for $4.95* plus shipping/handling?

The first time I bought an internal hard drive, I got a new IDE cable and a y-power cable in the box. Looking at even retail packaged drives lately, if you're lucky you might get a data cable. I even had one I bought come without a jumper to configure master/slave!

*All prices quoted are USD. Thank you for your business!