More than one accessory display?

[TCorzett]

I’m building-up a new computer for widescreen gaming and I’m trying to determine how to best set things up in Surround. My goal is to have a 3+2 (not in Surround) for day-to-day productivity stuff... then I'll switch into 3 monitors in Surround for widescreen gaming. I don’t yet have the cards or monitors to test the setup, so help is greatly appreciated.

I’m leaning towards two 1080 in SLI to drive everything, but looking at the Surround Configuration Tool it seems like only one “accessory display” is possible.

GeForce GTX 1080 2way-SLI With 2D Surround (Landscape)
> Orientation: Landscape
> Accessory Display: Yes, no additional GPU
> Maximum Resolution: 11520x2160
> Maximum Resolution (Bezel Correction): 12800x1600
> Maximum number of displays: 2-5 in Surround
1 Accessory Display

Special Instructions:
> Center (primary) Display of the Surround group should be connected to the left most card.
> Accessory Display must be connected to the card with most number of displays.
> You can use any connector to enable the Accessory Display
> G-SYNC and regular monitors can be mixed in Surround; effects of G-SYNC will only be seen on G-SYNC- enabled monitors

I don’t mind having to switch in/out of Surround in software, but I’d like to avoid needing to unplug monitors from the computer each time. Does anyone know what happens if two non-Surround displays are connected when setting-up Surround? Does one just go black? Does it cause errors?

For example… what would happen if I went with “Option 1”:


If I plugged in the three surround monitors into the Display Ports (left card port 1&3, right card port 1) and the extra displays into the bottom Display Port on both of the cards? The first extra display would be in a green square (= “Accessory Display”) and the second extra would be in a grey-cross (= “Unused”). Would that unused port/display just sit idle/black while in surround? or would it cause issues?

Would adding a third GPU (outside the SLI) to plug-in the two accessory displays make any difference?

Thank you for your help!

[scavvenjahh]

Accessory means "in addition to Surround" so these restrictions don't apply when Surround is off. If you have more monitors plugged in than you can (or want to) use with Surround, they'll just be deactivated during Surround configuration. Then they'll wake up when you return to extended desktop.
I think the best configuration is to connect all 5 monitors to the left/top card; if it's not possible, finding the "right" combination can be tricky in SLI+Surround, even with the official diagrams at hand...

Adding a third GPU would only make display reconfiguration quicker/easier, but might also cripple your mobo's PCI-E capabilities.

[landrass]

http://www.ebay.com/itm/ZOTAC-GeForce-G ... Swj85YOaWU

Try something like this PCI Express 2.0

[TCorzett]

Thank you for the responses.

If you have more monitors plugged in than you can (or want to) use with Surround, they'll just be deactivated during Surround configuration. Then they'll wake up when you return to extended desktop.

Great news!

I think the best configuration is to connect all 5 monitors to the left/top card; if it's not possible, finding the "right" combination can be tricky in SLI+Surround, even with the official diagrams at hand...

I should be able to connect all five monitors into a single 1080, but it will require running one HDMI -> Display Port (or DVI or VGA) adaptor for one of the accessory displays. I was under the assumption (although it may not be correct) that I’d be better-off running the displays using the same cable/connector type (e.g. all Display Port) from two cards… rather than trying to get them all on one card using an adaptor.

Adding a third GPU would only make display reconfiguration quicker/easier, but might also cripple your mobo's PCI-E capabilities.

The system will be running an i7-6850k so will have a max of 40 PCI lanes. Two GTX 1080 will use 16x each, so I’d have some lanes remaining if needed. I’ll also be running an M.2 SSD drive that will use 4x PCI lanes as well (and a PCI slot) that’s more important to me than the performance on the accessory displays.

Try something like this PCI Express 2.0

I have an older GTX card (mid-2012) sitting in a box some place; I’ll dig that out tonight to see the specs.

[stangflyer]

I run surround with 2 accessory monitors. For surround I use 3 x DP and 1xDVI. The fifth screen I use my mobo's hdmi using the intel gpu.

[scavvenjahh]

I was under the assumption (although it may not be correct) that I’d be better-off running the displays using the same cable/connector type (e.g. all Display Port) from two cards… rather than trying to get them all on one card using an adaptor.

It's tricky to find hard facts about this really. Although it seems you're more likely to be caught in a SLI/Surround connection nightmare when juggling multiple card outputs than using simple adaptors. YMMV.

Two GTX 1080 will use 16x each, so I’d have some lanes remaining if needed. I’ll also be running an M.2 SSD drive that will use 4x PCI lanes as well (and a PCI slot) that’s more important to me than the performance on the accessory displays.

It really depends on the mobo though. You may have 40 "theoretical" lanes but since you're not the one to assign them manually, with 4 cards plugged in it's not unusual to see 3 running at 8x, regardless of their individual specs. Not a big deal, esp. with PCI-E 3.0, but again it's a bit of empirical knowledge that may or may not have its use in your equation...

[TCorzett]

I run surround with 2 accessory monitors. For surround I use 3 x DP and 1xDVI. The fifth screen I use my mobo's hdmi using the intel gpu.

Unfortunately the motherboard/CPU doesn’t have an integrated GPU. In my current computer that’s what I’m using to drive my accessory display (the other two being plugged into a GTX 980).

It's tricky to find hard facts about this really. Although it seems you're more likely to be caught in a SLI/Surround connection nightmare when juggling multiple card outputs than using simple adaptors. YMMV.

I’m starting to get that feeling about facts, but everyone’s responses have been very helpful. Eventually it’s going to come down to plugging things in and trying to get everything configured using my hardware. Fortunately it sounds like even the “worst case” while in Surround isn’t the end of the world.

It really depends on the mobo though. You may have 40 "theoretical" lanes but since you're not the one to assign them manually, with 4 cards plugged in it's not unusual to see 3 running at 8x, regardless of their individual specs. Not a big deal, esp. with PCI-E 3.0, but again it's a bit of empirical knowledge that may or may not have its use in your equation...

Motherboard is an MSI X99 Gaming Pro Carbon. It’s listed as having four PCI-E x16 (Gen3) slots, but you’re right… who’s to say it’s going to do what I want [16x, 16x, 4x, 4x] and not switch into something like [16x, 8x, 8x, 8x] and degrade the performance on one of the SLI GPUs. I’ll do some more homework on this… good news is I’m unlikely to buy a third GPU for the two accessory monitors, since I have an older one laying around (and a 980 in my current system) that I can test with.

[TCorzett]

Motherboard is an MSI X99 Gaming Pro Carbon.

It helps if I go deeper into the specifications on their website and read the manual:

• 4x PCIe 3.0 x16 slots*
- Support x16/ x0/ x0/ x0, x16/ x16/ x0/ x0, x16/ x16/ x0/ x8, x8/ x16/ x8/ x8 with the CPU that supports 40 PCIe lanes.
- Support x16/ x0/ x0/ x0, x16/ x8/ x0/ x0, x8/ x8/ x8/ x0, x8/ x8/ x8/ x4 with the CPU that supports 28 PCIe lanes.
• 2 x PCIe 2.0 x1 slots
* PCI_E6 slot shares the bandwidth with U.2 port and M.2 PCIe 3.0 x4. Please refer to page 32 for PCIe 3.0 bandwidth table.

So it does look like the motherboard will keep the two SLI GPUs at 16x (with the extra one at 8x) however looking at the PCIe bandwidth table (page 32 in the manual) it would result in the M.2 drive running at only 2x (rather than 4x), which is less than ideal. Fortunately it sounds like there are several configurations that may work... looks like I'll have an excuse to test some different configs and run benchmarks!

There are also two PCIe 2.0 x1 slots on the motherboard (only one would be accessible while running SLI) that don't seem to come into play with the PCIe 3.0 interface.

[lerb50]

I use 3 accessory displays no problem. All hooked to 1card.

[landrass]

I run 3xPredator NVsurround,1xDK2 vr glasses,1x4k 165 cm UHDTV and 1x3d projector..I have i7-6850k 1070gpu in sli M.2 ssd,because of m.2 ssd i have to use this card http://www.ebay.com/itm/ZOTAC-GeForce-G ... 5YOaWU.And everithings works fine.

[TCorzett]

Thank you again for all the help. I've got the computer fired-up last night and have started getting the basic system stuff configured... using a PCIe 2.0 x1 graphics card (similar to what landrass linked) for the time being. Now I'm waiting to see what get announced at CES, then I'll make a decision on new GPUs/monitors.