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GTX 780 3gb and 6gb in SLI?

Last response: in Graphics & Displays
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June 30, 2014 6:48:28 AM

Is it possible to "mix" gpus with different amounts of vram? The plan is to get 2 GTX 780s with 6gb vram, and I have one with 3gb already. I´m thinking of buying one 780 6gb and sell my 780 3gb when I am close to be able to afford another 6gb one. Meanwhile I want to run the 6gb and the 3gb in SLI. Is it possible?

More about : gtx 780 3gb 6gb sli

June 30, 2014 6:53:28 AM

BambiBoyyy said:
Is it possible to "mix" gpus with different amounts of vram? The plan is to get 2 GTX 780s with 6gb vram, and I have one with 3gb already. I´m thinking of buying one 780 6gb and sell my 780 3gb when I am close to be able to afford another 6gb one. Meanwhile I want to run the 6gb and the 3gb in SLI. Is it possible?


More ram will not affect performance by much . Gtx 780 is already a beastly gpu and 2 gtx 780 3 gigs is more than enough to crack crysis 3 at ultra at 1600p and high on 4K . with good fps . 30 maybe .


Not sure if you can mix somegpu with different VRAM .
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June 30, 2014 6:53:39 AM

You can with AMD cards in crossfire, but Nvidia does not allow mixing of V-ram sizes in SLI. Sorry.
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June 30, 2014 6:54:09 AM

You can as long as they are both 780's (not say a 780 and a 780 Ti), however the 6GB card will only use 3GB of it VRAM.

I have done it before.
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June 30, 2014 7:22:35 AM

Really strange though, since my brother was not able to combine 2x GTX 280's one was a 2gb card and the other was only 1gb. Maybe they enabled using it since, lol. Learn something new every day. :) 
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June 30, 2014 7:22:38 AM

sincreator said:
Snipergod87 said:
You can as long as they are both 780's (not say a 780 and a 780 Ti), however the 6GB card will only use 3GB of it VRAM.

I have done it before.


According to Nvidia everything has to be the same.... http://nvidia.custhelp.com/app/answers/detail/a_id/100/...



I have done it and seen it done, not really sure what to say here.
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June 30, 2014 8:13:02 AM

Thinking just sell my 780 3gb when I get the 6gb one, and later buy another one.
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June 30, 2014 8:14:24 AM

dont forget if u get 2x3gbs 780 the videomemory doesnt stack so u basically have 2 3 gigs videocards.

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September 10, 2014 10:32:50 PM

BambiBoyyy said:
Is it possible to "mix" gpus with different amounts of vram? The plan is to get 2 GTX 780s with 6gb vram, and I have one with 3gb already. I´m thinking of buying one 780 6gb and sell my 780 3gb when I am close to be able to afford another 6gb one. Meanwhile I want to run the 6gb and the 3gb in SLI. Is it possible?


Buy a 6Gb GTX780 and run a 3Gb for PhysX ?

Plenty of buyers out there for a 2nd GTX 780?

P.S.
I wanted to do what you suggest because I don`t have room to put my 2.5-slot chunky GTX780 in the 3rd Z87 Sabertooth slot. Unless I get a bigger case: and total re-build.

Some games with heavy Game Mods already use more than 3Gb; even at 1080p.

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September 10, 2014 10:39:46 PM

It will not work. Maybe it might have worked in the past by those willing to use the Coolbits hack, but that was discontinued.

From the Geforce.com FAQ Nvidia SLI: What Works With What?
https://forums.geforce.com/default/topic/469402/

- All GPUs must have the same amount of VRAM and an identical Bus Width
-- You cannot use a "2GB" version with a "4GB" version or "3GB" version with a "6GB" version in SLI or a 1GB 192 bit bus with a 1GB 256 bit bus Etc.
Note: It used to be possible to enable SLI on cards with differing VRAM but this is no longer available.
Last Updated August 5th 2014
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September 10, 2014 11:55:00 PM

17seconds said:
It will not work. Maybe it might have worked in the past by those willing to use the Coolbits hack, but that was discontinued.

From the Geforce.com FAQ Nvidia SLI: What Works With What?
https://forums.geforce.com/default/topic/469402/

- All GPUs must have the same amount of VRAM and an identical Bus Width
-- You cannot use a "2GB" version with a "4GB" version or "3GB" version with a "6GB" version in SLI or a 1GB 192 bit bus with a 1GB 256 bit bus Etc.
Note: It used to be possible to enable SLI on cards with differing VRAM but this is no longer available.
Last Updated August 5th 2014


But you don`t say if you can use a single 6Gb GTX 780 as the main card; and an existing 3Gb model for PhysX ?

As PhysX appears to work independently of SLi.
Does it not?

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September 11, 2014 12:04:07 AM

I assume you're referring the the ASUS Strix 780 6GB. As stated, it will not work, I think the Strix will downclock to 3GB's of vRAM, I could be wrong and it might not work. Your best bet is to go with two 780Ti's, it will crush games in SLI. Crysis 3 at 1600P is going to kill your frames though. Expect 30-40 and expect microstutter to be evident as any Crossfire or SLI setup that isn't getting at least 45-60 frames plus is going to have visible microstutter. I can vouch this, I ran two 780Tis in SLI (about to in a few days again when my PNY Enthusiast aftermarket cooled 780Ti's come in the mail) and currently have a 290x crossfire. SLI is MUCH better about microstutter, though. Stay above 45 frames and you'll never notice, and 30-44 it's not going to be bad. Crossfire has evident microstutter at anything under like 55 frames. Take that into account. Honestly, if you want 6GB's of vRAM and performance a Titan SLi (Costly as hell but it'll get you there) or a GTX Titan Z (Not even worth it, just mentioning it, two titans would be better AND cheaper) would be optimal. Or you could go with the 290x at 4GB's. But honestly 3GB's of vRAM is a nice, good spot to be at right now. 4GB a bit overkill unless you play 4K and 6GB+ is straight up not needed.

My recommendations if you HAVE to have the extra vRAM.

GTX Titan / GTX Titan SLi (Very expensive, the performance is the same as a 780/780ti (in the middle really) but you get extra vRAM and the Black Edition reference card is SEXY)

R9 290/R9 290x/R9 290 CF/R9 290X CF (4GB vRAM, if you go with the 290x crossfire and overclock the cards a little you can have 780ti performance and 290x vRAM. A 780Ti overclock will always win in performance, though. Plus NVIDIA has superior drivers, but for price for performance the 290x is the way to go)

R9 295x2: In my opinion this is the single best graphics card out on the market right now. You get GTX Titan Z performance for only $1000 and it comes stock with liquid cooling. Price of one Titan, Titan Z performance, 4GB's vRAM (4GB mirrored, not 8GB) and the kicker, FACTORY liquid cooling. I love this card and wish I owned one. Hell, I wish I owned two! There's no better graphics card out right now and after it was cut to $1,000 this thing is a beast and it's cheaper than a Titan with Titan Z performance. You'll take a 2GB less vRAM hit, though.

GTX Titan Z: I only recommend this if you HAVE to have an NVIDIA card and you have three grand to shell out. This thing is a GREAT cart with a HORRIBLE price, so I'd never directly recommend it.

Otherwise, a 780 Sli will do just fine. Overclock them a nice bit and you can get close to 780Ti performance. You WILL be held at 3GB vRAM unless you come up with a second Strix. Two Strix cards in SLi would be very nice though.
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September 11, 2014 2:34:52 AM

Roger Rogers said:
17seconds said:
It will not work. Maybe it might have worked in the past by those willing to use the Coolbits hack, but that was discontinued.

From the Geforce.com FAQ Nvidia SLI: What Works With What?
https://forums.geforce.com/default/topic/469402/

- All GPUs must have the same amount of VRAM and an identical Bus Width
-- You cannot use a "2GB" version with a "4GB" version or "3GB" version with a "6GB" version in SLI or a 1GB 192 bit bus with a 1GB 256 bit bus Etc.
Note: It used to be possible to enable SLI on cards with differing VRAM but this is no longer available.
Last Updated August 5th 2014


But you don`t say if you can use a single 6Gb GTX 780 as the main card; and an existing 3Gb model for PhysX ?

As PhysX appears to work independently of SLi.
Does it not?



Yeah you can do that, but wont give the same performance benefit as SLI.
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September 11, 2014 2:44:45 AM

Don't be an idiot like me and end up with two graphics cards and no SLi bridge. Ugh.
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September 11, 2014 7:01:50 AM

Just don't connect the SLI cable and you'll have a primary graphics cards and a secondary PhysX card.
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