Andrew Savchenko <birc...@gentoo.org> writes: > Hi, > > On Sun, 05 Jun 2016 19:34:15 +0200 lee wrote: >> Hi, >> >> is there a way to reasonably use two graphics cards with a single >> display? >> >> SLI won't work because it's retarded in requiring the GPUs to be the >> same, which they aren't --- not to mention that the cards would be too >> far away from each other in the slots for a bridge to fit. >> >> So what I'm thinking of is like using one card as a default and being >> able to use the other one to play a video in some window on the same >> display, preferably managed by the same fvwm, with the window optionally >> being fullscreen in size. I'd like to do that because the card I have >> isn't powerful enough to play a video while an open gl application is >> running at the same time. >> >> I'll probably get a better card once prices come down a bit, but it >> might have the same problem, and why would I want to waste an otherwise >> perfectly good graphics card. > > Yes, but it depends on your hardware setup. What's yours and why > you need such unusual thing: connect two video cards to a single > monitor, or do you mean by display X display spawn over multiple > monitors?
a single monitor > In case of laptops such configuration is quite common: they may > have two video cards with single switchable output: intel card is > used for general work to save power and nvidia card is used for > applications, requiring high GPU performance. Switching is done > using sys-power/bbswitch. But looks like this is not your case, > since you are talking about card replacement, since most laptop GPU > cards are not replaceable. Right, it's not a laptop, and I don't want to switch between different cards. > If you want a multihead setup using two cards, this is trivial using > either xinerama or X screens depending on your taste. That is only simple when you have multiple monitors. > As far as I understand your e-mail, you are trying to mux video > outputs of two GPU cards to a single monitor (excuse me if I'm > wrong, but it is hard to understand what your hardware is), this is > also doable if your monitor supports dual input (most modern > monitors do). This way separate X screens may be used to achive > your goal. (Xinerama setup is also possible, but GL acceleration > will be limited to abilities of the weakest card). Exactly, but I don't want to use the picture-in-picture feature of the monitor, and I don't want separate X screens, and I don't have room to fit another monitor on my desk. I simply want to use one of the graphics cards to handle an application that uses open gl and the other one to play a video. > But honestly I don't get why you need this: if you have a powerful > GPU and it is not a laptop, where power consumption is critical, > why just don't use that card? Most cards have multiple outputs, so > it is not a problem to setup multihead with a single card either. The GPU isn't quite powerful enough for some of what I'm doing. Otherwise, it's a perfectly good card. So I need to get a better graphics card, and once I do, it would be a pity to have the current one laying around uselessly. I wouldn't get much if I tried to sell it, so I rather keep it in case I need a spare. Buying another one which is the same, to use SLI, won't help, either. IIUC, it takes some processing power to decode a video, so why not use one of the cards for just that? Multiple cards should be able to work together.
