I'm looking into putting together a new computer soon (first build for a noob) and I need a bit of help deciding on a GPU. I'm looking at either the 8800GTS 512 and then later SLI'ing them, or the upcoming 9800GX2. One of my deciding factors though is the use of a secondary display with SLI. I have read in countless posts that you are unable use dual monitors at the same time with SLI, but I can't find anything about switching between my monitor and my HDTV (I want to be able to use it as a HTPC as well) as a secondary. I know I can just unplug the monitor cable and plug in the HDTV one, but that is really a pain and an extra thing I have to teach countless times to the Mrs. Any help would be appreciated. Thanks.

So is this just an incredibly stupid question (probably) or doesn't anyone know the answer?

mmm... good question.

Should eb possible.


Although TBH if you are using just one at a time im guessing you wont be running games all the time? In which case you could always disable SLI to use both.

Couldn't you just plug the monitor into DVI port 1 and the TV into 2 and Mirror the two ports. I know if you have dual desktops it cuts your performance in half, but does mirror mode? This would give you the same picture on both displays w/o needing SLI or dual cards.

I'm assuming this is possible. I know something as simple as a splitter cable should do this for you, but if both the Monitor and HDTV aren't the same resolution...

This would work find if the Monitor and TV are the same resolution, but if it's beyond or under the native res of either, then that display probably won't display anything at all.

I think it may be easier just to swap between displays as needed if both the monitor and the TV differ in native res.

When I switch my display from the PC monitor to the TV, I don't need my PC monitor to still be functional. I just use only the TV as my monitor (so I can watch movies, I don't really need to game on it). For instance right now with my old computer I have a ATI 1650pro and when I want to watch a movie I just go inot my Display Properties and turn on my secondary monitor and turn off my primary monitor (it just goes to black when I click apply). I dont see why I couldnt do this with SLI since I'm not using two monitors simultaneously, but you never know. Thanks for the advice.

It's going black because the resolution you're trying to output doesn't match the native resolution of the TV, most likely. What type of TV is it and what resolution is your monitor currently running?

With Sli enabled you will still have output to both DVI sockets on the primary card whilst in 2D mode (maybe even to all four, I don't know for sure) but as soon as you go into 3D mode i.e gaming, all the output is switched to one DVI socket.

I have a 40" 720P Samsung LCD and a Sony 17" LCD for my monitor (however I am upgrading to a 24" monitor). The resolution difference doesnt matter when choosing primary display or secondary display because you can set the settings to which resolution you want and once you activate the certain display, those settings are enabled. I am doing this through the display properties/settings.

What mousemonkey said about not being able to use an alternate display only when gaming seems to make sense. Thanks for the help.

You're welcome.