Multi-Monitor, Multi-GPU Personal Experiences (AMD & nVidia)

[dac7nco]

OP, I game at just a bit over your resolution; I use 3x 1920x1200 in portrait, which is just ~.7MP larger. When ATI Cypress came out, I read Anandtech & HardOCP reviews and bought a pair of 5850s (I still have one). The 5850s worked well in a lot of games, but ATI/AMD (IMO) suffers from abysmally low minimum-FPS, especially when crossfired. I have a pair of nV cards now for Civ-5 and FSX (I don't play a lot of shooters, and I rarely have time to play anything), but they are MORE THAN enough to get by at close to 7MP. IMO nV has the better 3-monitor experience, but with AMD, you get it with 2-slots of real estate, instead of 4. This isn't said enough, but turning down IQ settings a bit in modern games doesn't really change the experience. If you're playing XXX on high vs. ultra, but on 3 monitors vs. 1, who's laughing now? If you can deal with the amateurish AMD drivers for (a small few) games, than AMD has the performance, price and memory crown. If you feel like paying 2/3ds of a month's rent for a pair of GTX580s, then there you go.

Daimon

As a side note, nV is a bastard when they design their low to mid-end cards. If you could tie together three mid-range GTS/GTX cards, this would be a moot point... I used to run GTX460SLI @ 2GB/Card, but I couldn't add a third... why wasn't there a second connector for Tri-SLI? - because that would've kept me away from buying 580SLI, at less cost (and more memory!).

 

[Jovec]

Connecting multiple monitors will increase the idle clocks/power usage too, even if those monitors are turned off. It doesn't sound like much, but on my 6950 measured with a kill-a-watt device, I measured a 33 watt increase when connecting the second monitor. Normal, single monitor idle on my 3.8 1090t system is around 105 watts. For someone like me who only occasionally uses the second monitor, this is a large wattage penalty.

I have not investigated it, but Nvidia may run at "normal" idle clocks if both monitors are the same resolution, at least with newer cards.

Nice little review.....................

Here is another good one. Take a good look at tri gtx580's vs 3 6970's. 6970's in x-fire and tri fire have too many N/A 's

It's the crossfire bridge failing at that large resolution - not enough bandwidth for 3x 260x1600. As the resolution was dropped tri/quad Xfire was working. Still a limitation to be sure.

 

[WetNinja]

cocoreno, Civ 5 looks amazing in Eyefinity portrait mode. How did you get it to use that mode?

I'm running three 1920x1080 monitors in portrait mode (3240x1920), but when I go into the Civ 5 options, only single-monitor resolutions are available.

 

[gorobei]

Connecting multiple monitors will increase the idle clocks/power usage too, even if those monitors are turned off. It doesn't sound like much, but on my 6950 measured with a kill-a-watt device, I measured a 33 watt increase when connecting the second monitor. Normal, single monitor idle on my 3.8 1090t system is around 105 watts. For someone like me who only occasionally uses the second monitor, this is a large wattage penalty.

I have not investigated it, but Nvidia may run at "normal" idle clocks if both monitors are the same resolution, at least with newer cards.

incorrect. It is a monitor issue, not a card issue.

http://www.tomshardware.com/reviews/radeon-hd-6990-antilles-crossfire,2878-3.html

"PowerPlay saves power via engine voltage, engine clock, and memory clock switching. Memory clock switching is timed to be done within an LCD VBLANK so that a flash isn't seen on the screen when the memory speed is changed. This can be done on a single display, but not with multiple displays because they can (and in 99% of the cases, will be) running different timings and virtually impossible to hit a VBLANK on both at the same time on all the panels connected (and when we say "timings" it’s not as simple as just the refresh rate of the panel, but the exact timings that the panel's receivers are running). So, to keep away from the end user seeing flashing all the time, the MCLK is kept at the high MCLK rate at all times.

With regard to power savings under multiple monitors, we have to trade-off between usability and power. Because we can't control what combinations of panels are connected to a desktop system we have to choose usability. Other power saving features are still active (such as clock gating, etc.) so you are still saving more power than peak activities. Note, that in a DisplayPort environment we have more control over the timing and hence this issue could go away if all the panels connected where DP."

since NV wont even natively support displayport, it will always have the multi-monitor idle penalty. If AMD ever comes out with a driver fix, an all dp card like the eyefinty6 could potentially idle like a single monitor.

 

[aka1nas]

What are your thoughts/experiences about Crossfire support in general and running alongside Eyefinity in particular?

I was previously on a GTX 260 tri-SLI setup with 3x24-inch panels on Nv Surround. I've also had two other SLI setups prior to that. I switched to my 6870 this time around due to all the issues with Nv Surround and the GTX 200 series (no Tri-SLI support, had to either disable cards to run Surround, or disable monitors to run full Tri-SLI). I am finding that Eyefinity is a bit smoother to enable and use, but the single 6870 is still a tad weak for 5760x1200 gaming with games from the last 18 months or so.

Do you feel that I would get any benefit from adding a second 6870? I've read a lot of articles in the past where Crossfire scaling seems to be relatively poor and more title-dependent compared to SLI.

 

[digitaldurandal]

What are your thoughts/experiences about Crossfire support in general and running alongside Eyefinity in particular?

I was previously on a GTX 260 tri-SLI setup with 3x24-inch panels on Nv Surround. I've also had two other SLI setups prior to that. I switched to my 6870 this time around due to all the issues with Nv Surround and the GTX 200 series (no Tri-SLI support, had to either disable cards to run Surround, or disable monitors to run full Tri-SLI). I am finding that Eyefinity is a bit smoother to enable and use, but the single 6870 is still a tad weak for 5760x1200 gaming with games from the last 18 months or so.

Do you feel that I would get any benefit from adding a second 6870? I've read a lot of articles in the past where Crossfire scaling seems to be relatively poor and more title-dependent compared to SLI.

To their credit the scaling is much improved.

I will say I have 2x570s and no issues in surround.

 

[Dark Shroud]

My 23" wide screen dell is enough for most things. But I hooked up an old 4:3 LCD monitor that I have as a 2nd screen for productivity when I need it. I've had no issues running multi-monitor setups with my AMD cards.

 

[sandorski]

Random comment regarding Bezels - Some people are just going to be annoyed by such things, while others will adjust to it. I remember back in the CRT days, the old AG vs SM debate. Practically everyone acknowledged the superior Output on AG Monitors, except for one(or 2)thing, the Hair sized Damping Wire(s) that only showed on Light colours and usually required some effort to find.

The issue regarding Bezels will never end, simply because there is always going to be some gap no matter how small the bezel gets.

 

[cocoreno]

@WetNinja

cocoreno, Civ 5 looks amazing in Eyefinity portrait mode. How did you get it to use that mode?

Once I setup the three monitors for Eyefinity in Catalyst Control Center, I was able to select 3240x1920 as my default resolution, which Civ 5 picked up when I launched.

@sandorski

Random comment regarding Bezels - Some people are just going to be annoyed by such things, while others will adjust to it.

Pretty much. They don't bother me, and for the Dell ones I'm using, I actually thunk they are on the smaller side. Not that I wouldn't mind them smaller, but the trade-off of having so much screen real estate in your face when gaming *does* feel different than a single monitor. Even a single 30" monitor, which I use on my primary system.