Is having a second GPU for second Monitor worth it ?

[Ecthelion]

Hi guys, 

 

So I have two monitors : The main one for gaming is plugged into my GPU (GTX 970) and the secondary one (mainly for browsing internet and stuff while gaming) is plugged into my motherboard (so it uses my CPU graphic processor I suppose). 
I recently acquired a old GPU (GTX 660) from disassembling an old rig, and I don't know what to do with it. Since my CPU is getting pretty old (i7 4790k), it starts to struggle sometimes while in game and I was wondering if adding the GTX 660 into my rig and have it operating the second monitor would be beneficial for my CPU performance (since it won't have to deal with the monitor on it's own) ? Or is it totally irrelevant ? 

[MysteriousAeon]

I would just connect both monitors to your GTX 970. Why not? It's a good card and that's what I had been doing since I got my second monitor with my deceased R9 390. Also your i7-4790k isn't "getting old", it still holds up pretty well I have mine OC'd to 4.6GHz. If you're getting low FPS in some games it's probably related to your GPU.

[Cereal5]

You could fold on the 660  But no. You do not need a second GPU for two monitors lol. Just plug it it, it doesn't matter.

[Bananasplit_00]

The I7 4790K is still really good, if anything is holding that rig back its the 970. Anyway just plug all the screens into the 970, it's not going to hurt performance

[Origami Cactus]

33 minutes ago, Strike105X said:

 Even having the monitor connected to the IGPU does nothing. Processing and VRAM usage is still mainly done on the main 970 gpu, the only advantage you can have from this is if you use intel quicksync video for recording or encoding, that is where the IGPU will be used, but NVIDIA has a dedicated part for this on its GPU's and it handles it better even with a game loaded, so again useless. I would just disable the IGPU and hook both monitors to the GPU it usually works better like this to, 

Eeeeh.

I have to disagree. Why does taskmanager show the gpu/vram usage of the igpu and main gpu separately if it is " all done by the main gpu"?

Also how are the igpu and the main gpu connected internally? Doesn't make sense to me.

 

You are mainly right that having both monitors connected to the main gpu wont hurt/gain any performance, as web browsing isnt gpu intensive.

[Origami Cactus]

1 minute ago, Strike105X said:

Maybe i should have said it otherwise, most software isn't designed to use them separately, microsoft for example with directx 12 implemented a way that two different gpu's can be used for processing a single game, but it ended up being useless as nobody used it in their games so far. There are some specific purposes where to some extent it can be done like mining (and maybe folding ? I have neither been able to confirm or not this) but otherwise not much is designed to use two different GPU's properly, you might see some spikes up to 3% there, but that's within the margin of error of it just existing/being turned on. As for how they are communicating ? Like everything else they are connected through your motherboard of course, but generally nothing more is done then sending the visual signal, as the processing in most cases is done by the main gpu.

But in his use case they are perfectly used separately. He has some programs open on one monitor, and a game open on the other.

The programs which are one the monitor connected to the igpu all use the igpu, and the game that is on the monitor that is connected to the 970 uses the 970.

I know that if he wanted to play a game using both monitors then it would use only the 970,

 

but in the use case of having game on one monitor and the browser on the second monitor both gpus are utilized separately just fine

[Origami Cactus]

7 minutes ago, Strike105X said:

That's where i'm saying your wrong, just because its outputted through the port connected to the IGPU it doesn't mean its processed by the IGPU, its processed in both cases by the 970 and the visual signal then sent through the igpu towards the second monitor.

Last time i tested it, it wasn't the case, but as my current cpu doesn't have an igpu i can't test it.

Seeing as you have both a dgpu and an igpu, i will just take your word for it, until proven false.