[deathskater]

so it's a simple question will I have any problem doing Sli with a 1gb GTX 460 and 1 768mb reason of this is because the cheapest I find a 1gb for 99.99 on newegg some people have told me the 1gb card will just run at the performance of the 768 card other people say they simply not compatible so in the end what's the truth?

 

[PrimeBurn]

Not compatible.

 

[UBERmorrison]

I don't think its a matter of the cards being compatible, but your mobo (Gigabyte GA-880GM-UD2H) has the same 880G chipset as mine, and they don't support SLI! I'm pretty sure there's a patch for it though.... so maybe more hassle then it's worth?

 

[deathskater]

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131636 I'm getting this motherboard so it's not a problem lets stick to subject on the cards please

 

[UBERmorrison]

Fair enough man. Yeah they should work as their the same GPU. Linus Tech Tips did an episode on SLI! I'll find it for you....

 

[UBERmorrison]

[ame]http://www.youtube.com/watch?v=XS5rBS8n-LM[/ame]

Boom

 

[TheReaperWaits]

Will the registry hack (forget what its called) (COOLBITS!) not work for Fermi cards?

 

[deathskater]

Quote:

Originally Posted by UBERmorrison;14166391
http://www.youtube.com/watch?v=XS5rBS8n-LM

Boom

Just the response I was hoping for thanks rep+ for you I'm a happy camper now

 

[The_Rocker]

They will work. Just you will be limited to 768mb across both cards.

 

[Anthraxinsoup]

Both cards won't work! I don't know why people say otherwise. The Memory bus width difference makes it impossible to work together. Sorry dude

 

[deathskater]

I just noticed why it was so cheap it only has 288 cores while my 768mb has 336 so definetly will try to spend a bit more for a propper 768mb anyone know if sparkle has a good customer service? thats my next in line

 

[TickleMeElmo]

Quote:

Originally Posted by deathskater;14166575
I just noticed why it was so cheap it only has 288 cores while my 768mb has 336 so definetly will try to spend a bit more for a propper 768mb anyone know if sparkle has a good customer service? thats my next in line

All GTX460s have 336 CUDA cores, that doesn't change; I don't know where you got your information, but it is wrong. The difference is in the memory bus and the ROPs .

You cannot SLI them because either Nvidia doesn't want you to or there is some technical restraint, either way it's not something you can change. If you want to SLI different models go to AMD.

 

[Anthraxinsoup]

Quote:

Originally Posted by TickleMeElmo;14166608
All GTX460s have 336 CUDA cores, that doesn't change; I don't know where you got your information, but it is wrong. The difference is in the memory bus and the ROPs .

You cannot SLI them because either Nvidia doesn't want you to or there is some technical restraint, either way it's not something you can change. If you want to SLI different models go to AMD.

The 460SE is what he's looking at. Also, it's due to different Memory Bus on the cards.

 

[PrimeBurn]

He was looking at a 460 SE.

EDIT: Again...

 

[deathskater]

Quote:

Originally Posted by TickleMeElmo;14166608
All GTX460s have 336 CUDA cores, that doesn't change; I don't know where you got your information, but it is wrong. The difference is in the memory bus and the ROPs .

You cannot SLI them because either Nvidia doesn't want you to or there is some technical restraint, either way it's not something you can change. If you want to SLI different models go to AMD.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814130690 This is the item I was looking at. I may not be an expert on this stuff but certainly know how to read.

 

[PrimeBurn]

Just to clarify:

GTX 460 - 336 Processor Cores and 256-bit memory bus
GTX 460/768 - 336 Processor Cores and 192-bit memory bus
GTX 460 SE - 288 Processor Cores and 256-bit memory bus

None of these can SLI with each other.

 

[TickleMeElmo]

Quote:

Originally Posted by Anthraxinsoup;14166616
The 460SE is what he's looking at. Also, it's due to different Memory Bus on the cards.

This doesn't stop AMD from letting users Crossfire completely different models. What I was trying to get at was if it's an artificial limitation (in the same way PhysX with a non Nvidia card is blocked) or an actual architectural limitation (like how one Nvidia card can't drive more than 2 displays even though AMD cards are more than able to do this)

 

[EvoBeardy]

Quote:

Originally Posted by PrimeBurn;14166776
Just to clarify:

GTX 460 - 336 Processor Cores and 256-bit memory bus
GTX 460/768 - 336 Processor Cores and 192-bit memory bus
GTX 460 SE - 288 Processor Cores and 256-bit memory bus

None of these can SLI with each other.

This, the reason you can't SLI a 768MB with a 1GB is due to the Bus Width, whoever told you about the VRAM dropping is correct with certain cards, but only on say a GTS 250 1GB with a 9800GTX+ 512MB, wherein the VRAM size size will drop down to 512MB for both cards. Or a 2GB 460 with a 1GB 460.

The SE has a second SM cluster disabled, so it's core differs from the other two 460's.
Quote:

Originally Posted by TickleMeElmo;14167145
This doesn't stop AMD from letting users Crossfire completely different models. What I was trying to get at was if it's an artificial limitation (in the same way PhysX with a non Nvidia card is blocked) or an actual architectural limitation (like how one Nvidia card can't drive more than 2 displays even though AMD cards are more than able to do this)

nVidia is not AMD, just like AMD is not Intel, some things have allowances, where other things don't. It's one of those things.

Also, I thought AMD's could only CF the same series, I.E 58XX with 58XX, but not 58XX with 59XX or 57XX?
Yeah it's still more versatile, but hey:- It's the way it's meant to be played.

 

[Droogie]

You can't sli a 1gb 460 with a 768. They're too different. Different amount of memory, different memory bandwith, and the 768 has fewer ROPs. Not compatible.

Should have read above, but must say it again. Also, don't go for the SE. You'd be better off picking up a used 460 of the marketplace here. They go real cheap.

 

[brettjv]

Quote:

Originally Posted by Droogie;14168327
You can't sli a 1gb 460 with a 768. They're too different. Different amount of memory, different memory bandwith, and the 768 has fewer ROPs. Not compatible.

Should have read above, but must say it again. Also, don't go for the SE. You'd be better off picking up a used 460 of the marketplace here. They go real cheap.

Agreed. Although I'm about 98% sure the physical problem is with the memory bus width exclusively.

You can find examples (esp. with ATI/AMD) of cards successfully (sometimes needing to be hacked to work) doing multi-gpu with specs that are mismatched in pretty much every other regard: Stream Processor counts, ROP counts, memory amounts, heck even with DDR3/DDR5 mixed ... but TTBOMK there's never been an example of two cards doing multi-GPU with different memory bus widths.

I don't know for sure that it's an architectural limitation (in fact, I can't reckon why it would be, esp. using Alternate Frame Rendering), but it seems like it probably is, otherwise we'd have seen at least one example of it somewhere.

Edit: Come to think of it, I also can't recall a case where cards w/different CUDA (aka Shader) core counts could do SLI, but as it's possible with the AMD analog (SP count), I have to think that's not a physical limitation ... but I'm not positive on that.

Now, if it IS the case that one can successfully SLI 460's with 768MB + 1GB (192-bit bus width + 256-bit), then ... scratch what I said above

But (again, ttbomk) I don't believe anyone's done multi-GPU with cards with mismatched memory bus widths ... hack or no hack. Except with Lucid Hydra chipset, of course.