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Forums -> Multiple monitors -> Multiple PCI Express video cards
Christian Studer   2004-10-07 21:24
PCI Express seems to be ideal for installing multiple video cards, unfortunately it's not that simple due to not all slots being compatible with video cards. See Multiple PCI Express video cards for more on this.

Christian Studer - www.realtimesoft.com
ECarlson   2004-10-08 13:57
It's too bad they didn't just make PCI Express x16 the one and only type of slot, then you could have lots of video cards if you wanted, and you could put any card in any slot.

I didn't realize they had 5 types of slots. The motherboards I looked at online had one x16 slot for video, and a handful of x1 slots for everything else. In many ways it doesn't seem much different than having one AGP slot and a bunch of PCI slots, and perhaps an ISA or AMR slot.

Seems such of a waste to make a new slot type, and not make it one universal slot type: That was my hope when I first heard they were coming out with a new slot type: Imagine how convenient that would be.

In any case, I hope dual x16 slots becomes standard soon.

- Eric, www.InvisibleRobot.com
Christian Studer   2004-10-09 08:30
My feelings as well. I also don't know why they don't just make all slots x16, even if the actual speed of the slot is lower, for example one slot running at x16, the others only at x1.

This seems to be technically possible, for example on my Dell the x8 slot is actually running at x4 speed, but you can insert x1 through x8 cards.

Christian Studer - www.realtimesoft.com
Louis Evans   2004-10-10 14:13
Some of the PCIe motherboards also have a "APG-express" or G.E.A.R. slot for a APG card. One such motherboard is the GIGABYTE GA-8I915P Duo-A
Christian Studer   2004-10-24 22:20
There will be a version of the nForce4 chipset with dual PCIe video card slots, the nForce4 SLI.

The chipset has a total of 5 PCIe slots: two x16 slots for video cards, and three x1 slots for other cards.

The x16 slots are most likely only running at x8 speed with two video cards inserted, the chipset has a total of 20 PCIe lanes, and a single x16 slot running at full speed would require 16 lanes.

According to Nvidia's press release, motherboards with the new chipset should become available before the end of the year.

Christian Studer - www.realtimesoft.com
ECarlson   2004-10-25 13:07
Thanks for the update. I also read a little about it on www.Geek.com a few days ago. Here's their article.

- Eric, www.InvisibleRobot.com
xoff   2004-10-25 18:25
Do you think it would bez possible to connect 3 monitors with a sli dual card based system ?
I am eager ti play IL2 with my 3 monitors (got a parhelia at that time but poor framerate
Thx for answers
Regards
Lydell Aaron   2004-11-03 07:18
Supermicro, makes a variety of motherboards with multiple PCI-Express slots. One in particular, the X6DAi-G, a motherboard with two PCI-express x16 slots, one of which is x8 speed. I just spoke with Supermicro technical support and they said that they have confirmed that many video cards from ATI and nVidia work perfectly in the x16 slot that runs at x8 speed. If this is the case, then this would open the possibility of running two x16 video cards.

One side note is that today's video cards that run at x16 do not even come close to saturating the bandwidth available from even the x8 speed. In fact, these video cards don't even saturate the AGP 4X and 8X busses. This is implicitly stated in the Neoseeker article, A Look at PCI Express and explicitly in the Dell article PCI Express Technology.

Lydell Aaron
35   2004-11-04 00:14

(1) No SLI capable mobo is dual 16x. (except 1).
They will be all 16x and 8x, BUT the modes when SLI is enabled is either 8x for both video PCI-Express slots or one 16x.

This is because chipsets can only provide 32 lanes for a typical PCI-Express mobo. If you have two 16x, what happens to other sub-systems?! That's why you'll see 16x and 8x slots. (even then they only work at 8x each in SLI mode).

The only exception is Tyan's dual NF4 chipset mobo which uses two NF4 chipsets to provide more than 32 lanes. (it is rumoured to provide true dual 16x). It is for a dual Opteron CPU setup, so it'll be VERY expensive.

(2) When SLI is enabled, only 2 video outputs are available. ie : it only outputs to the primary video card. The 2ndary does not output anything. This is because this mode is essentially tricking the OS into thinking its 1 video system.

(3) When you disable SLI (remove that connector), the two video cards are treated as 2 separate systems and only then can you have 4 displays.

Under this situation you can have ANY brand video card (as long there is 2 of them same)...ATI, XGI, etc. Only in SLI mode is this Nvidia specific.

(4) Performance-wise, PCI-Express 16x does jack all...Not even 4x does much for video (next to no improvement), so dual 8x in SLI is more than sufficient.

(5) Aside from Alienware's Video Array, ATI is also on the bandwagon with their own dual PCI-Express setup. At the moment, its undergoing beta testing, rumours say they are currently calling it "Multi-Rendering". This name will change as it is released in retail as of halfway through 2005 (maybe this time next year).

(6) Alienware's Video Array is different because it allows you to install 2 video cards (as long as they're the same), from any brand (XGI, ATI, Matrox, Nvidia, etc)...

Rumours have it that Alienware is gonna licence the technology to Iwill. Iwill originally help develop the mobo for the Video Array, BUT were not allowed to make a retail (end-user) motherboard with this technology.

It appears they will be able to, once this agreement is sorted out. This means you can build a setup in the future with Video Array WITHOUT paying $$$$$$ to Alienware. :)
xoff   2004-11-05 01:44
Hi,

To summarize it a bit you mean that to be able to get 3 head diplay while running one game (il2 for example) Nvidia Sli mode won't allow more than 2 display at a time. Sad thing.

So I got to go on with my poor parehlia still ?
Thx for answers
Best regards
Walter   2004-11-13 09:32
Where can I get a x8 PCI-e card, all I see are x16 video cards?

Thanks!
Christian Studer   2004-11-14 01:48
I don't think there are any x8 PCIe video cards, you would need to get a system with dual x16 slots or use a standard PCI video card.

Christian Studer - www.realtimesoft.com
ivc   2005-01-05 17:04
Asus recently released two SLI motherboards with two x16 slots (SLI x8, x8), the A8N-SLI and the A8N-SLI Deluxe. I'm not interested in the SLI mode, only the ability to run two seperate x16 cards.

Would it be possible to put two these cheap x16 Nvidia PCIe cards (total 2xdvi,2xvga) in the slots and span the destop horizontally via the dvi connectors? And later maybe two seperate monitors on the vga connectors (since horizontal span only allows two monitors)?

If this is possible it would make a damn good setup for lcd monitors with a relatively low cost.

-ivc
ECarlson   2005-01-06 13:43
ivc: I doubt it. I think horizontal span mode only works when the 2 monitors are connected to the same video card. Of course, you can still extend your desktop across as many monitors as you want, but not with the special horizontal span mode. You could always buy a single card with 2 DVI connectors and get horizontal span capabilities that way.

I'm hoping that someday the multi-monitor capabilities of OSes and apps will improve to where there is no longer any need for the horizontal span mode. Multiple monitors should just work - without any need for special tricks like horizontal span.

- Eric, www.InvisibleRobot.com
keith   2005-03-18 17:48
You do not have to remove the connector to disable SLI. It is disabled at the control panel
djdaveathome   2005-04-20 18:42
Just to let everyone know, SLI technology only supports a single display in sli mode. You have to disable sli through the display properties and reboot to get your second (up to 4 monitors depending on the video card) monitor to work.

it reaaaally sucks althoug I do register a whopping 19400 on graphic benchmarks ( 2 x 6800gt) I prefer to run dual monitors and so, sadly , the second graphics card sits like a lump most of the time while I'm working.

They bragged it could support 2 on their web FAQ, they then sneaked in and changed the wording to say, "only supports a single monitor." no hint of a driver fix like they were hinting a short time ago.

Dj
Jason McMinn   2005-06-20 10:53
DJ -

How is the performance of two Nvidia 6800 cards with SLI disabled?

I am waiting to run three Dell 24 inch LCD displays at 1920x1200 on a new Alienware box.

I know that Nvidia has a tech not that says you can disable SLI and support up to 4 displays.

I am assuming each monitor is it's own - meaning that you can can three separate 1920 x 1200 displays running at the same time.

Thanks,

Jason
Connex   2005-07-03 02:08
Can somebody post the steps on how to setup 3 monitors on 2 PCI-Express cards please?

MONITORS:
I have 3 ViewSonic VP191b
Analog 15-pin mini D-subx2
Digital Digital DVI-D

MOTHERBOARD:
Asus A8N-SLI Deluxe (2 SLI ports)

VIDEOCARDS:
2 PCI-Express NVIDIA 6800
Connex   2005-07-03 02:31
Can somebody post the steps on how to setup 3 monitors on 2 PCI-Express cards please?

MONITORS:
I have 3 ViewSonic VP191b
Analog 15-pin mini D-subx2
Digital Digital DVI-D

MOTHERBOARD:
Asus A8N-SLI Deluxe (2 SLI ports)

VIDEOCARDS:
2 PCI-Express NVIDIA 6800

I forgot to mention this:
OS: WinXP Pro SP2
Robert   2005-07-07 05:40
I'm running two GeForce 6600 PCIe cards with SLI disabled. I gotta say when it works it's great but the problem i keep running into is that to get both cards to work properly i pretty much have to reinstall XP. Generally when the driver changes the second card stops functioning. i get the little warning splat next to it in my hardware manager list. It doesn't recieve any resources from the system (irq, memory ranges, etc..) and therfor the system won't start the device.

it's almost like the system sees two identical cards using the identical drivers and it gets confused and thinks that the second card has resources when it doesn't. No ammount of uninstall / driver rollback / reinstall with new or older version drivers seems to fix the problem once this problem happens. The only way i've been able to overcome the issue is to reinstall the OS. At this point unless i can find a way to resolve this problem i'm serously considering removing the second card and just running both of my monitors off of the main card.

The motherboard i'm using is a MSI K8N Diamond
zima   2005-07-13 10:46
Solution:

http://www.realtimesoft.com/multimon/forum/messages.asp?Topic=5132&tmpl=

:)
Bart   2005-07-24 02:02
Hi, I need to send 6 different images to 6 tv-outs. I guess I need a motherboard with 5 pci's and 1 agp and fill them up with videocards with tv-out. The only thing is that I'm afraid ultramon doesn't support setting the TV-out from ntsc to PAL. Does anyone have any tips on how I could manage this?

Thanx, Bart
Dev   2005-08-20 02:08
Can somebody confirm me whether 'S3Virge DX' PCI card will work on 915G motherboard for multi monitor display. I want to surf the net as well as do my MS office work on the other monitor

If 'S3Virge DX' PCI is not compatible then kindly suggest me other PCI cards that will work
I dont have any graphics work nor do I play Games. So pleease suggest me some cheap PCI card or PCI Express card

GOD Bless
zima   2005-09-21 01:06
Hello Christian, I just noticed, while looking more closely at specs of G550 PCIe at Matrox site that the primary analog output actaully supports 2048 x 1536, and only the second is limited to 1600x1200. Perhaps it's worth correcting this info on news page...
Christian Studer   2005-09-22 23:42
The way I've read it you only get 2048x1536 if you have only a single monitor connected, with two monitors both monitors are limited to 1600x1200.

I got the display resolution information from www.matrox.com/mga/corp/enterprise/products/gseries.cfm.

Christian Studer - www.realtimesoft.com
zima   2005-09-25 09:01
Interesting...outputs on Matrox cards are rather...independent. Oh well, I guess one could always post question on Matrox support forums...I don't care enough for that ;P
eirk   2005-09-26 01:48
im a newbe to the computer seen and cant figure out what is better pcie or agp. and those video cards that have two dvi plug ins, do those support two different monitor or will i have to get another card. thanks gusy

erikhoover
ECarlson   2005-09-26 14:03
PCIe is the new replacement for AGP (Don't get the old PCI, unless you have a specific need), so you want PCIe if you are buying a new computer. The cards with 2 DVI ports will support 2 monitors, and either monitor can be digital or analog.

- Eric, www.InvisibleRobot.com
Fernando   2005-10-06 03:05
Hello all,

I hope this helps.

I am currently putting together two PCI Express cards on a Dell Precision Workstation 470 using a Catalyst 16x to 8x PCIe adaptor.

The Dell system has a 16x slot and an 8x slot. The 8x slot supposedly runs "only" at 4x. I got the Catalyst adaptor 16x to 8x and inserted a nVidia Quadro NVS 280 PCIe 16x and it runs just great. On the 16x I have setup a standard ATI X300 PCIe.

Everything is running under Red Hat Enterprise 4 (xorg). I want to believe Windows would not complain during the setup/install. I had to do some tweaking but nothing complex. At this moment I have three independent monitors.

I am about to buy another Quadro NVS 280 to setup 4 monitors.

Cheers,

<>< F
Jacky   2005-10-06 10:59
Hi all,

I have a so-so onboard/integrated video card on my motherboard but since I wanted to use dual monitors as well as to play some 3D games, I decided to buy a Nvidia PCIe GeForce 6600 card and it arrived today.
My ideal plan is: 1 monitor per video card, play games in my new card. Now problems appeared:
1. If I set my new card as the primary card in BIOS, my on-board one will disappear.(No signals received in my monitor)
2. If I set my on-board card as primary, my fullscreen games will run on my on-board card, which is not I want of course.

So any ideas to help me achieve my goal? Thanks in advance.
Tantalus   2005-10-07 01:53
have you tried redefining the primary display under your windows display settings?

you should be able to do this since windows doesn't care what the primary display is. the bios setting is really just for initialization purposes and for POST display. once windows starts loading its startup files, the primary display becomes whatever display is defined under windows, not what's under the bios.
Jacky   2005-10-07 02:42
The most interesting thing is, after I clicked my monitor #2 (the monitor connected with my new card), checked the "Use this device as default" in the Windows display setting, and finally clicked the "OK/Apply" buttons, nothing happened. The checkbox was unchecked automatically. I have no idea why it is so.
Tantalus   2005-10-07 06:16
doesn't the 6600 have dual-output? is there a reason why you're not using the 2nd output?
Jacky   2005-10-07 07:10
Yes it has two outputs. My reason is sort of stupid. I don't want to waste my OnBoard one.

OK so let me ask a question: can I set my new card as primary in BIOS, while my Onboard still be usable? Thanks.
ECarlson   2005-10-07 12:11
The onboard probably takes away system memory, so if you disable it in BIOS, and use the new card only, your OS and apps will have more memory to use. If you already have a Gig or two of RAM, it might not matter, but if you only have 512.Meg, I'd use the card only.

- Eric, www.InvisibleRobot.com
Jacky   2005-10-07 20:57
I have 1.5G RAM.
ECarlson   2005-10-08 09:27
That's plenty of RAM, but I think (maybe someone can verify this) that there is still a performance hit when the computer has to use the onboard RAM as both video display memory and as regular system memory.

I thought I read something to that effect recently.

- Eric, www.InvisibleRobot.com
Fernando   2005-10-18 07:41
It can be done (read my previous posting for history)

2x video cards, pci express, one on the 16x slot and the other on the 8x slot running at x4 with a Catalyst adaptor ($275). I have a Dell 470n with two nVidia Quadro NVS 280 (one from PNY and the other from Dell) and RedHat WS 4.0.

After some tweaking it is working with no additional software except the nvidia driver and a proper xorg file.

If redhat can I bet Windows will with even less troubles.
Fernando   2005-10-18 07:41
I forgot to mention that I get 4 monitors working as independent or expended desktop.
dan bretz   2006-01-24 08:59
Hello I need some assistance. I am trying to hook up 2 monitors. When I put in the Gforce 5500 PCI video card, It disables my onboard video. There is NO option in the bios to enable it and when i go to device manager, it says "This device can not start." My friend says I might have to "flick" the bios... I tried to reenstall the bios but it doesnt help. I am running a Dell optiplex gx1. kind of old but there has to be a way to get my onboard to register.

dan
Brad   2006-03-19 13:17
Can someone clarify the statement that multiple monitors are not supported in SLI mode? My computer has 2 Geforce 7800GT cards in SLI mode and an additional PCI video card (Radeon 9200 Sapphire). Currently, I can't get my machine to recognize the PCI video card. Is it a lost cause? It seems like SLI shouldn't have a bearing on a completely separate device, but I can't figure out what might be wrong.
John Zitterkopf   2007-07-23 15:48
All PCIe cards; to get compliance must operate in x1 mode; as well as their native mode.

Most video cards work in all modes.. x1, x2, x4, x8, x16; although I've only tested with the Nvidia line.

Adapters (lane converters) are cheap.
http://www.adexelec.com/pciexp.htm#PEXP4-SX-4/1

P/N DESCRIPTION
PEXP4-SX-4/1 X4 TO X1 CONVERTER
PEXP8-SX-8/4 X8 TO X4 CONVERTER
PEXP16-SX-16/8 X16 TO X8 CONVERTER
PEXP16-SX-16/1 X16 TO X1 CONVERTER

I have personally used the PEXP16-SX-16/1 and the PEXP16-SX-16/8 converters. If you email them; I'm somewhat sure they'd make you a 16-4 or 16 to 2 converter.
I think the cost is less than $30.

I have no affiliation with this company; just happy with their products.

Killer Mod: http://www.zittware.com/mod/Killer/
ATTN2Detail Mod: http://www.zittware.com/mod/ATTN2Detail/
G35 MacMini Mod: http://www.zittware.com/mod/G35_mini/
Ricky   2007-07-28 07:55
Can I use the Onbard for 1 monitor, 1 PCIe 16x slot for the 2nd monitor and 1 PCI 1x slot for the 3rd monitor ?

Is this sure to work? or I will need to try with several config's?

Thanks !

Cheers,
Ricky
Len Osborne   2007-08-01 07:41
Christian
There are several Intel motherboards with multiple PCIe x16 slots. We use them daily in our QuadStation systems. Contact me with any questions.
Belisarius   2007-08-19 05:55
Hi,

Been running three monitors for a while. Two on a NVIDIA AGP 6600GT and a ELSA Synergy on PCI. Looking to upgrade my system and going dual/quad core.

Mobos nowadays seem to have 2 PCIe slots for SLI cards. I assume SLI is not compulsary so could I put two low-end PCIe cards with dual DVI and run 4 monitors? Or does it have to be a non-SLI setup simply with 2 PCIe 16x slots?

Cheers

Andy
Christian Studer   2007-08-19 06:49
The cards don't need to run in SLI mode, as long as the system has two x16 PCIe slots, you'll be able to install two video cards.

I use two Quadro FX3500 cards for a total of 3 monitors.

Christian Studer - www.realtimesoft.com
Belisarius   2007-08-19 09:02
Thanks Christian, just wasn't sure on that.

I'm hoping to plug in 2 22" LCDs on one card and my existing 17" LCDs on the other. My other concern is whether a card with 2 DVIs will run the two big montors at the sme time. I assume there is a limit on the resolution the card can run when driving two monitors?

Andy
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Forums -> Multiple monitors -> Multiple PCI Express video cards

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