Can I use two gpu's for their ports?

Ruppe · Jan 3, 2015

Is it possible to put two of the same gpu's into my pc, and use the hdmi port on each gpu for an extended display? Thanks!

Darkbreeze · Jan 3, 2015

Yes, but you can't use them in Crossfire or SLI and still use the ports on both cards. As independent GPUs, you can. Be aware that with two GPUs installed you're also going to need a very good quality PSU of higher capacity than you have now, unless you already have a very good one with some headroom.

Ruppe · Jan 3, 2015

Darkbreeze :

I have a 750W psu. Do you think I can keep this psu and be okay to get another gpu? Here's my parts list...
AMD FX 6300
Sapphire Radeon R9 280X VaporX
8gb DDR3 Crucial Ram
WD 500gb hard drive
240gb ssd
240gb ssd (I have two ssd's)
asus m5a97 mobo
Corsair H100i
2 40mm fans

Darkbreeze · Jan 3, 2015

As I said, the quality is what matters. A cheap 750w PSU usually won't put out sustained voltage at the same level as a good unit of only 550w without having problems. Plus, voltage noise, ripple and poor regulation all affect your hardware but especially the GPU, CPU and motherboard. What is the model number of your PSU? It should be right on the PSU label or tag.

Are you trying to do this in order to game on multiple monitors, or just to extend the desktop to multiple displays?

bystander · Jan 3, 2015

Darkbreeze :

As he is using AMD, it works out as you said, but just for accuracy, Nvidia does not restrict you to 1 card in SLI.

bystander · Jan 3, 2015

Ruppe :

What is the plan here. Are you going to Crossfire for more power, or are you just looking for an extended desktop, and only looking for a way to enable it cheaply? You can use a DP to HDMI converter if all you want to do is connect a couple displays via HDMI. You might also look on the back of the monitors to see if DVI is an option for one of them. HDMI is not better than DVI for picture quality and there is no good reason that I can think of that you need to carry sound to two different monitors.

Darkbreeze · Jan 3, 2015

Agreed.

Darkbreeze · Jan 3, 2015

bystander :

I'm a bit dumbfounded as I've always been under the impression SLI had the same port restrictions as CF since I read this on the Nvidia website. Can you confirm this?

With GeForce R180 drivers (or later), standard SLI configurations for 2-way, 3-Way, and quad SLI support a maximum of two monitors. Additional monitors (up to 6 monitors total enabled) may be enabled by using either a motherboard GPU and/or a PhysX capable graphics card (GeForce 8 series or higher with at least 256MB of memory) that does not have the same GPU as those that are SLI enabled.

bishopi5 · Jan 3, 2015

I can confirm that both SLI and CF share the ports (one cards ports do not exist)

Darkbreeze · Jan 3, 2015

Well, that seems to contradict what bystander is saying.

Mousemonkey · Jan 3, 2015

I have just started playing about with two 660Ti's and four monitors and I can see why there are contradictions on what works and what doesn't, at one point I've had a game (BL2) running across all four monitors which according to Nvidia you can't do with 2D Surround!

tiny voices · Jan 3, 2015

I have used ports on both the top and bottom card in my SLI setup before to run my dual monitors. You are supposed to use the ports on only one card, but the ports on either card can be used in SLI. Not sure about CF.

bystander · Jan 3, 2015

bishopi5 :

Check out Nvidia's own setup manual: http://www.geforce.com/whats-new/guides/how-to-correctly-configure-geforce-gtx-680-surround#3

This may have changed with the 600 series, but Nvidia does allow the use of both cards, although there are some restrictions too. I can confirm it works, as I've tested it.

Looking at the layout, at first glance it appears that if you want to use any connector on the bottom card, you have to have used that connector on the top card as well. Kind of weird, but it works.

tiny voices · Jan 3, 2015

^that is only for surround. If you are only running two monitors, you can use any ports you want. Due to lack of cables at the time, I was using the HDMI from the top and bottom cards in my 660ti SLI setup to power my dual monitors. No problem. For non-surround, you can even use the bottom card's ports only if you wanted to.

bystander · Jan 3, 2015

tiny voices :

Yeah, well, I couldn't find a link to setting up extended displays, but either way, it proves that both cards can be used, though I think I read somewhere that with extended displays, they are supposed to be connected to which ever card has the most monitors connected to it.

Mousemonkey · Jan 3, 2015

bystander :

At the moment I'm using the DVI's of both cards to run four monitors but as they do not share the same native res I am expecting some funky behaviour.

Darkbreeze · Jan 3, 2015

Ok, thanks guys. So I think we've established that unlike CF, which positively doesn't allow it, SLI may allow use of ports on either card, but may have some limitations as well. It still leaves the option of using two cards in SLI if the OP wants to game, and be able to have a wider variety of options for outputs, or simply use dual cards without SLI, if he doesn't need gaming firepower and simply wants two native dual link DVI outputs or two native HDMI outputs. Keep in mind, if you plan to use refresh rates above 60hz with 1080 or higher resolutions, it won't happen on HDMI. You'll need to use dual link DVI or displayport outputs for that.

Mousemonkey · Jan 3, 2015

Darkbreeze :

At the moment my cards are not in SLi, with SLi enabled I will only have the use of the two monitors that are plugged into the primary card.

Darkbreeze · Jan 3, 2015

tiny voices :

Just to clarify, the question at hand is really whether or not ports on both cards, not either card, can be used. For example, as outlined in the OP, one HDMI from both cards, when in SLI, or only if they are not in SLI. It had been my understanding for years, as construed by the Nvidia document I quoted from earlier, that you could not simultaneously use outputs from both cards when they are configured in SLI.

bystander · Jan 3, 2015

Darkbreeze :

Somethings changed when the 600 series came about. Prior, you had to use SLI to get surround, and you'd have to use connections from both cards. With extended monitors only, while using SLI, only one card can be used, and with Surround and extended monitors, then 1 card can only be used for the extended displays, but both cards can be used with the Surround monitors, but only if the same type of port was used on the primary card.

But ya, there are limitations, and it might be just easier to read the setup link.

Can I use two gpu's for their ports?

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