Topic Title: 7970 crossfire with different non-reference cards 3GB + 6GB
Topic Summary: Does it work?
Created On: 07/29/2013 07:03 PM
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 07/29/2013 07:03 PM
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BingoMaJoM
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Hi I have a 7970 Ghz edition non-reference (Lightning) from MSI and I'm planning to buy an other one, but I think I need more videoRAM because I'm running an Eyefinity setup, so I'm thinking to buy a 6GB card (Toxic edition) from Sapphire, and drop them to crossfire, with the 6GB card in the primary slot.

Will this work? If clock speeds are problematic can I down-clock them?

Thanks in advance for help guys :)

 07/29/2013 08:47 PM
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Thanny
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Assuming they work (which is probable, but I can't say for certain), you'd still be limited to the lower memory amount of 3GB per GPU.

 

 07/29/2013 09:06 PM
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BingoMaJoM
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thanks for your anwser

so then will I have 6 gigs of usable VRAM? I mean i want to run the recent games (battlefield4, crysis3) in eyefinity, in really high res (5760x1200, maybe 7680x1440) and I plan to keep this setup for several years, so the cards would be using 3 + 3 from theirs own (first card uses 3 of 6, and second 3 of 3) or the two cards would be using the first cards 6 gig with sharing?

I realized that is impossible to have 9 GB with a 3GB and a 6GB, I just want 6GB total for the two

I plan for years, and I think  3 gigs of ram for this res will be not enough to run

 07/30/2013 02:02 AM
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UcouldBrong
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No information is given on the mobo, psu, etc.  you are using, but, you may want to research going with a 3 card Crossfire Eyefinity setup; especially with the upcoming drivers...

Another option would be to go with 2 cards and get one of the higher resolution monitors coming out.  7970's have plenty of headroom for overclocking; especially the GHz Editions.



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 07/30/2013 10:18 AM
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BingoMaJoM
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I didn't think that in this case my spec is relevant, but here it is:

ASUS Maximus V Formula
Intel Core i7-3770K @4.4Ghz /w Corsair H100i
Corsair Dominator Platinum @2133MHz 4x4GB
MSI R7970 Lightning BE
Corsair HX850W

Sometimes I did OC on my 7970Ghz, but I dont run it always further clocked than the factory OC, because I don't like seein the temp goes above 80 °C.

So I have a 5760x1200 setup, I think I keep this if I cant run higher res. I don't want to be limited to one screen; ago, I decided to chose this manufacturers card because I wanted the brilliant Eyefinitys good stuff.

What is your advice? I just want than 5760x1200, highest settings on most recent and upcoming games.

 07/30/2013 01:34 PM
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UcouldBrong
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Get the EXACT same card.

Be sure the EASY PLUG on your mobo is connected to the 4 pin power connector!

 

Get a Cougar CF-V12HP PWM or a Panaflo fan and attach it to the back of the computer where the gpu's exhaust in lieu of the expense and complexity of watercooling them.  This will ASSIST in removing large amounts of heat from the case. 

MAXIMIZE case cooling and airflow.  Spectre fans have very large cfm ratings with low noise.

Overclock the cards INCREMENTALLY and adjust the card fan speeds to maintain ~80C (easier in winter) and hopefully ~50% fan speeds or higher if you can stand the additional noise (place tower in the hall or another room).  You'll find that the 2nd video card will run slightly cooler than the top card so the fans can be adjusted accordingly.

Increase Power Control in CCC incrementally.

Experiment resulting framerates by changing multisampling modes, etc.

 



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 07/30/2013 03:13 PM
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BingoMaJoM
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thanks your anwser, I'm considering.

I've alredy pluged in the molex connector to the mobo. I don't know it's necessary for only one cards, but I think I don't do any risky.

My case airflow is not so bad at the moment, but if its necessarry I will upgrade, but in my country (Centarl Europe) there aren't as many types of products, so I limited to some manufactures products, I have 2 spectre fans for intake already.

My chassis has 140mm intake in the front and in the bottom, and 2 140mm exhaust on top and 1 on the back. I have a mesh on the sidepanel, few months earlier I had a 120mm fan here, but I can't decide which way I want to use it (you know: intake or exhaust).
The intake fans are Spectre fans, and the exhaust fans are Thermaltake 1800 RPM LED fans.

The watercooling is not my way, cause this is a non-reference card, and as far as I know there aren't any waterblock manufacturer, who pruduces waterblock to this custom PCB, and I dont want to putter with the gpu-only-blocks wich don't cover the rams and VRAMs etc..

I just wary of overclockong because of the huge ammounts of bonus heat, but if they can stay "cool" and 80C is OK than I will be SO-SO HAPPY with

 07/30/2013 05:04 PM
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black_zion
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Attach it to the side panel as an intake.

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 07/30/2013 08:17 PM
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Thanny
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I doubt any games would present a problem with three 1920x1200 screens in 3GB.  I play at 2560x1600, and with the exception of Tomb Raider prior to patching, I've never seen any game go beyond 2GB graphics memory usage.

 07/31/2013 12:42 AM
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BingoMaJoM
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Still now the RAM usage goes above 2gigs eg. if I play BF3 , Crysis 3 or Tomb Raider. Especially if I throw in AA and very high/ultra texture settings.  That's why I started to worry :\

Only I ask (sure that I will not, but just asking): If I sell and go with a Titan it would be better?

 07/31/2013 01:30 AM
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UcouldBrong
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Not really.  Read the reviews.



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 07/31/2013 09:11 AM
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black_zion
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If you sell and go with a Titan you are an idiot. Dual GTX 770s or 7970s are much cheaper and faster assuming the game supports multiple GPUs.

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 07/31/2013 11:31 PM
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UcouldBrong
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No...the dumb idea would be to step down to 770s when you already have a BETTER card....chaaaaa!



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 08/01/2013 09:11 AM
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black_zion
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I have yet to see any reputable review site show that the HD 7970 Ghz consistently scoring statistically significantly above the GTX 770, with the GTX 770 scoring above the 7970 Ghz in some games and the 7970 beating the 770 in others by single digits each way, with the 770 having more consistent frame pacing while being slightly more efficient. Take the AnanTech review for example. So tell me again why the 7970 Ghz is a BETTER card than the 770 rather than an equal?

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 08/01/2013 03:09 PM
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Thanny
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Originally posted by: BingoMaJoM Still now the RAM usage goes above 2gigs eg. if I play BF3 , Crysis 3 or Tomb Raider. Especially if I throw in AA and very high/ultra texture settings.  That's why I started to worry :\

 

Only I ask (sure that I will not, but just asking): If I sell and go with a Titan it would be better?

 

With a single card or two?  The reported memory with two cards is cumulative.  Divide by two get the actual memory usage per GPU.

 

 08/02/2013 11:06 PM
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UcouldBrong
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bzzzz....AnandTech for reviews of computer hardware??  Cellphones...maybe. 

You can win the discussion as I'm not going to waste more time finding the reviews....my recollection is that in MANY cases the 7970s OFTEN surpass 780s let alone 770s (depending on game, application, cf/sli, etc.) , but if you are a fan of Nvidia products....live on, pal.



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 08/03/2013 01:04 AM
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black_zion
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Yea I don't blame you for not wasting any time trying to find reviews where the HD 7970 "OFTEN surpasses" the 770, because the TomsHardware and Neoseeker reviews say the same thing, they are for all intents and purposes EQUAL cards. And unlike you, I am not a fanboy.

But to the OP, it will be ideal if you get an identical card to the one you have now, or as close as you can get as there are often minor revisions through the card's run. Don't worry to much now about running out of VRAM, even if you are using 2GB VRAM that's still plenty left. You could always turn down AA as well, at the texture sizes games use today and resolutions you play at, I doubt you would notice much difference between 2x, 4x, and 8x.

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AMD FX-8350 w/ Corsair H105, ASUS Sabertooth 990FX Gen3/R2, 8GiB G.SKILL DDR3-2133, XFX HD 7970, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, Corsair C70, HP ZR2440w, Win 7 Ultimate x64

Edited: 08/03/2013 at 01:14 AM by black_zion
 08/05/2013 01:17 PM
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RoyMacDonald
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Originally posted by: BingoMaJoM thanks for your anwser

so then will I have 6 gigs of usable VRAM? I mean i want to run the recent games (battlefield4, crysis3) in eyefinity, in really high res (5760x1200, maybe 7680x1440) and I plan to keep this setup for several years, so the cards would be using 3 + 3 from theirs own (first card uses 3 of 6, and second 3 of 3) or the two cards would be using the first cards 6 gig with sharing?

I realized that is impossible to have 9 GB with a 3GB and a 6GB, I just want 6GB total for the two

I plan for years, and I think  3 gigs of ram for this res will be not enough to run



Edited: 08/05/2013 at 01:30 PM by RoyMacDonald
 08/05/2013 04:23 PM
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black_zion
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For 6 1920x1200 monitors no 3GB will not be enough, but neither will dual 7970s or GTX 780s. Get a second 3GB card if you must have it now else wait a couple of years and get new hardware.

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AMD FX-8350 w/ Corsair H105, ASUS Sabertooth 990FX Gen3/R2, 8GiB G.SKILL DDR3-2133, XFX HD 7970, 512GB Vertex 4, 256GB Vector, 240GB Agility 3, Creative X-Fi Titanium w/ Creative Gigaworks S750, SeaSonic X750, Corsair C70, HP ZR2440w, Win 7 Ultimate x64
 08/06/2013 03:48 PM
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RoyMacDonald
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2560x1600 is 4096000pixels. 5760x1200 is 6912000. That's almost 70% more processing power. Custom PC tested several games at those reolutions and only the HD 7990 GHz, GTX690, GTX Titan 6Gb  cards could run Crysis 3, & Bioshock Infinite at the 5760x1080 resolution. All those cards are £800 plus. Adding another 7970 ghz edition will let you run at that resolution for a lot less money. Any higher resolutions will need a third card. I should add that they tested with all the bells and whistles turned on in those games.



Edited: 08/06/2013 at 03:58 PM by RoyMacDonald
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