• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

GTX 670 SLI for triple monitor

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

FishD

Member
Joined
Sep 8, 2002
Location
Dublin, lreland
Hi all,
Just got a single 670, and am happy with it. However ive seen some discussions criticising the limited memory bandwidth and its effect on performance when using very high resolutions.

Would the addition of another 670 in SLI improve the memory bandwidth, as it might be an option for me a little down the line.

Cheers
 
Hi all,
Just got a single 670, and am happy with it. However ive seen some discussions criticising the limited memory bandwidth and its effect on performance when using very high resolutions.

Would the addition of another 670 in SLI improve the memory bandwidth, as it might be an option for me a little down the line.

Cheers
Do you have a 2gb or 4gb version of the 670? Graphics memory isn't additive...your total ram will be the lowest. For example, if you use a 2gb + 4gb card (not entirely sure if this is possible), gddr=2gb (2+2=2, too).

If you have a 2gb card....what games do you play? The biggest gddr killer atm is modded Skyrim. For that, you definitely want to consider going with a card that has 3-4gig. If you play BF3, that could also do with the extra memory for your resolution (5760x1080 I'm guessing?).

For most other stuff you should be fine. If you already have a 2gb card and you don't play memory-intensive games, definitely consider adding a 2nd 2gb card as your fps and/or eye candy will improve significantly. If 60% fps increase sounds worth it, that's what (imho) would be a realistic and conservative expectation. On some games I get over 80%.
 
Most any modern games will stress your setup. A single 670 has a tough time at that res. Metro2033 brings most rigs to their knees.

Guess the question still remains...get another 2gb card or start over and grab a 4gb one (or 2). Notice that in the review, they don't show 670 2gb sli framerates. You might want to google around to check the memory usage at your res with the games you play. For almost everything you're going to see a good bounce from going sli but if the game uses more than 2gig of memory you're gonna be stuck.

If money were no object, I'd ditch the 2gb card and go with a pair of 670 4gb ones. That said, it's a lot of cash and if your games all use less than 2gb the switch wouldn't be worth it.

EDIT: Check out the graphs on this page... http://www.hardwareluxx.de/index.php/artikel/hardware/grafikkarten/22235.html?start=16 . Granted...that's with super-sampling but if you've got surround and 1-2 nice cards...figure eye candy's part of what it's all about. Again, though...that's Skyrim (would imagine BF3 multi-player cranked up is similar)...search around for any info using your games.

If you can't find any real stats AND can find canned benchmarking apps for the games you play, I can test them for you (using 4gb cards) and report back with vram usage numbers. If you want to take me up on that offer, could do it today otherwise won't be able to get to it until next weekend.
 
Last edited:
Here are the Metro2033 results. Memory usage peaked at 2.057gb for a moment but was pretty steady at the 2.022 mark.
 

Attachments

  • metro2033-benchresults.png
    metro2033-benchresults.png
    829.7 KB · Views: 1,098
Cheers for the offer and info Funsoul, but If i can measure the memory bandwith on my own rig, i can get a better feel for how the larger resolutions throttle the system. I've read through the article again, and can find no reference to 4gb cards. I appears to me that they were using 2gb cards for the review, but maybe mistakenly called it 4gb SLi.

I'm still getting my head around the memory stuff, but from what you are saying, SLI doe not improve the memory bandwidth Over a single Card is that correct? So if a game has a large memory overhead (say due to high AA and resolution), no matter how many cards u line up in SLI mode, will be limited by the card with the smallest memory? I guess there's some very technival reasons why the memory in SLI is not just additive.

The game i need this rig to perform with is not even out yet so im trying to future proof my rig for it. (ARMA 3)

Its not an option for me to ditch the 2gb, would loose too much. Question is it worth the upgrade, or live with single monitor, till some time in the future when i upgrade again.

And finally, i cant see your images, only the thumnails. Dunno why.

Any adivce on measuring memory bandwitdh on my rig would be greatly appreciated.

Cheers
 
Sli has no additive effect on memory amount so even if you got a 4gb card (and could actually Sli it...which iirc is not possible) you'd still only have 2g of available.

Adding another card will def give a fps boost but whenever memory needs go over 2gig you'll be bottlenecked (so massive drop in fps until the memory needed drops). Basically, you'd have to reduce res and/or graphic settings to get a playable experience.

To see the attachment, right-click and open it in a new tab.

To capture your in-game mem usage use msi afterburner. Set it to log memory usage and save the results to a file. Start your game with afterburner running.

Net, net suggest you stay single monitor with your current card.
 
Last edited:
ARMA2: Operation Arrowhead Demo Benchmark (5760x1080, single player, scenario 8, all settings at highest possible) takes a max of 1220MB gddr...adding a 2nd 2gig 670 card would definitely hook you up but no idea what ARMA3 will push.
 

Attachments

  • arma2-maxed.png
    arma2-maxed.png
    301.2 KB · Views: 1,028
Thank again Funsoul.

I guess with all this DX11 eye candy the memory requirements are going to go up on future games, so 2gb will be limiting at high resolutions. Ran metro full on, with 87% (of 2gb) usage and only 1920x1200 !!. But i guess i don't mind single monitor for those type of games (since most of the perhiperal vision is dark anyhow!! )

I do need it for my 'trackir' games, ie, DCS10, BMS, and ARMA, Rise of flight. I can make it in ARMA2, even got to 85%, with view distance max, but this was with 5760x1080. If i were a betting man, i would bet that ARMA3 is not going to be as demanding, on memory, but hey i think your right, since i can play what i need to now, hold off till ARMA3 comes around (but i'm a Frame rate junkie, so it will be difficult.)

cheers for you efforts and help. Hope others find the thread useful
 
Back