sli/crossfire question.

6 replies [Last post]
RobinHoodxBlade
Offline
Joined: 12/16/2012
Posts: 41

i found a faq page that answered alot of my questions but i have a few like....

1.) im only deciding to get a 2nd card because my computer laggs when i try to play games while watching movies on my other tv (1280x720 for tv and 1440x900 on computer screen) which i calculated to be slightly above
the max output on my graphics card(http://us.msi.com/product/vga/R6770-MD1GD5.html#/?div=Specification)

so what im wondering is getting a 2nd card my best choice? will it even fix the issue?

2.) i read that SLI/CF lowers to the lowest speed and does NOT double the memory just shares. is this true?

Basics that i thought was answered:
how does SLI/CF work? does it double the memory?(e.x. 2x1gb card = 2gb?)
does it double the max output?(e.x 3000x2000 on 2 card = 6000x2000?(if i put 1 display to each card?))
will it enable me to have more then 2 monitors? because atm my card supports 2 and looking to enable a 3rd.
can i dedicate a card just for my TV?(e.x plug tv in GCard 2 and 2 Monitors in GCard 1 and have 0 lagg(unlike #1)
is there a performance delay or anything like that from using SLI?(lagg)
can i still transfer between monitors/tv if plugged into different cards?(mouse movement between them)
is there a way to boost 200-300 pixels for max output?(external memory?)
is the max output decided on the graphics cards memory?

thanks for any and all questions you can resolve.

spawnkiller
spawnkiller's picture
Offline
Joined: 05/06/2012
Posts: 310

2X1gb = 1gb cause the 2 cards need to stock the texture to work...

Same max output by connection but better resolution total = 3 monitors at 1080p (if your gpu powerfull enough) but you can't do 1 single monitor at 6000*2000 (it'll be 3 monitors in eyefinity mode)

If each card support 2 monitors, you would be capable of running 4 of them

In theory all outputs will be shared so even if you have a monitor in the second one it'll be the same...

No lag but not all games/programs scales equally so in one game you can see the double the FPS but in the other it'll be slower than a single card (then you need to disable SLI in the driver to run it correctly)
**And that's why i wouldn't do SLI/Crossfire and prefered to have a single better card

Yes you can share your desktop or do an Eyefinity or Surround (up to 6 screens seen as a single big one)

No, you can't have more Pixel than your monitors resolution (you can't have more memory on your GPU than the default configuration from the manufacturer)

No but if you don't have enough memory, the performance will degrade really fast (1gb is for a single 1080p with maxed out details) You can turn off details to emprove high resolution performance (turning off details free memory needed to store a high resolution image)

PS: 1080P = 2 073 600 pixels per image and if you go higher 6000*2000 = 12 000 000 pixels... So 2 1080p monitors will be 4 147 200 pixels and 3 will be 6 220 800 pixels and that's why you need more memory on your GPU...

Gaming PC: MSI Z77A-G45 ::: Intel Core I7 3770k @ 4.83Ghz ::: EVGA GTX680SC Signature ~1300mhz Boost/7122mhz ram ::: 16GB 4*4gb G.Skill 2240mhz CL10 ::: ASUS Xonar DX ::: Crucial M4 128gb (windows) + Intel 330 180gb (Steam games) + 1TB Caviar Black (storage) ::: Cooler Master Silent Pro Gold M1000 ::: Antec P280 ::: Noctua NHU12P SE2 ::: ASUS VE247H ::: Logitech G510 ::: Cooler Master Storm Sentinel II ::: Logitech X530 ::: Steelseries Siberia V-2 Black & gold edition

98% Of people under 25 surround their minds with rap music, if you're part of the 2% that stayed with rock, put this in your signature, ROCK IS BETTER!

RobinHoodxBlade
Offline
Joined: 12/16/2012
Posts: 41

well this answered most/all of my question but one thing i still dont understand....

on this Page :http://us.msi.com/product/vga/R6770-MD1GD5.html#/?div=Specification
(graphics card specs)

it says "Display Output (Max Resolution) 2560x1600"
would SLI extend this in a way? by this i mean if i had 2 cards (same exact) and 1 monitors at 2560x1600 in card 1 and 1 monitors at 2560x1600 in card 2. would it lag/would it support that high of an Output?
(taking that each card can handle those resolutions without lag)

or is that even my issue? because i noticed that you said something about the different programs/games having different FPS caps will cause lagg or something?(the game im playing is Fiesta(MMO by Outspark(soon to be gamingo))

"2X1gb = 1gb cause the 2 cards need to stock the texture to work..."
what do you mean by stock the texture?

final question is :

does my graphics card support having HDMI(1280x720) and VGA(1440x900) running at the same time?
if they do will it support a game? because i notice it ONLY lags if i have something demanding playing on the VGA(a game).

Sorry i didn't understand ^^

spawnkiller
spawnkiller's picture
Offline
Joined: 05/06/2012
Posts: 310

It will work but Max resolution is on "desktop" as in game with that resolution, you'll need a really beefy card to run anything smoothly (it will start but you'll have like 1 fps as the card isn't powerfull enough for a high resolution like that...)

2 card will be pushing more fps out of this but will not add more resolution and if you add another monitor, it'll be the same 1fps as both card will deliver 1 screen... (however if you we're driving dual monitors with a single card at 1fps it'll still (in theory) double the FPS)

Don't know about this specific games but your card is powerfull enough for a 1440*900 resolution so i think you don't have enough memory on your GPU to run dual monitors out of it (is it ok with just one screen ??)
You could try to lower details or disable Vsync, motion blur or post-process depending on your game's options...

For the Graphic ram question, It needs to have all the textures needed to produce the image but each card can't take the needed textures anywhere else than it's own memory so each card will stock the same thing ex: a game have 890mb of texture to load, it'll be loaded on both card...

If you run out of memory, the GPU will store all others info on the CPU RAM and that will take cpu usage, cause lags spikes and affect performance...

If it's only lagging when you do something intensive on a screen, it's because the card surely want all the power to that screen and lower the refresh rate on the other to save the power for the game running OR it simply can't handle both at the same time OR it's trying to have the same fps on both but your TV can't handle 60fps (normal TV is 24FPS) so that cause visual lag even if it's not really lagging...

RobinHoodxBlade
Offline
Joined: 12/16/2012
Posts: 41

its a HD tv and the movies are running at 60 FPS when the game is NOT running(cant test with atm because movies are being watched ^^)

but you might be right about it being a gpu memory issue being that its only when i have a game running/high demand.

is there a way to run 2 cards without sli? where they are not helping each other? like 1 card takes the load of a movie/etc while the main card runs Games ^^?
e.x
2 PCI ports
1 card in 1
1 card in the other
second card has HDMI port being used to run movie
first card is using VGA port to play game

first card ONLY stores textures/memory on its memory
2nd card Only stores frames for movie on its memory

is that possible? is it just plugging a 2nd card in? if not is there a program that can do this?

p.s thanks for helping so much ^^ i guess im getting a bit repetative to understand how sli works ^^

spawnkiller
spawnkiller's picture
Offline
Joined: 05/06/2012
Posts: 310

No it isn't possible at my knowledge, the only thing that can be done is Physx doing by a single Nvidia card when any GPU will run other part of the game... Maybe someone have "hacked" a AMD or NVIDIA driver to do this but i've never seen that as a powerfull card is enough to do this and people generally just upgrade or plan it for a few weeks later...

You can't use both card separatly but if you had 2 GPU that will eliminate GPU bottleneck problems and the only thing that would possibly cause lag will be the GPU ram quantity...

** i'm thinking about if you change the priority of your media player to high in the Task manager if that will help as the GPU and CPU cycle will be directly used for your movie over the game (and movie don't need much in general so it'll only affect a little the game performance)

RobinHoodxBlade
Offline
Joined: 12/16/2012
Posts: 41

thanks for the tip on the priority that REALY helped ^^ only issues is occasionaly the audio
video will get out of sync by about half a second of :/ but its fine ^^. also is it normal for a computer
to crash from setting to real time? and whats the difference from real time and high?(i know speed but how much fast is real time to cause a computer crash/lagg to force shut off)