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Can you do SLI with an 8800 GT and a 9800 GT

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April 27, 2009 5:27:29 AM

Hi

I hear that both the 8800 GT and the 9800 GT are the same. DOes that mean I can run both in SLI? The 8800GT is not easily available anymore in my part of the world and hence the question.

More about : sli 8800 9800

a c 130 U Graphics card
April 27, 2009 5:50:16 AM

Technically. Yes. The rule for SLI is that it has to be the same chip which it is. They are both a G92 core so should be fine, i have not run said configuration myself so cant say 100%.
But according to the rules it should be fine.

Mactronix
a c 169 U Graphics card
April 27, 2009 5:51:39 AM

Hello and welcome to the forums mate :) 

No u cant,the cards have to be exactly the same,there is one way to do it though and its flashing the BIOS of your 8800GT(This is a risky option and its not recommended)
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a c 130 U Graphics card
April 27, 2009 8:31:16 AM

Really ? I know you know what you are talking about Maziar, just seems strange that exactly the same chip cant be used in SLI just because the sticker is differant.

Has anyone actually tried it ? I have read the Nvidia FAQ and it says this.

In order to provide optimal symmetric scaling, SLI technology requires the NVIDIA GPUs to match. For example, a GeForce 7800 GTX must be paired with another GeForce 7800 GTX. Likewise, a GeForce 6600 GT must be paired with another GeForce 6600 GT. However, using the latest Release 80 or later graphics drivers, NVIDIA GPUs sold by different manufacturers can be used together in an SLI configuration. For example, a GeForce 7800 GT from vendor ABC can be matched with a GeForce 7800 GT from vendor XYZ.

Now what i read was that its "Optimal" to have the "GPU's" matching. note they dont say the cards. Also they are talking about 7800 GTX cards here, now i dont know personally but i didnt think that back then you would have had two differant cards made using the exact same core. Same core yes but with things dissabled etc, so they would be physically differant.

I hope you can see where im coming from with this

@ rubik_azariah

Sorry if it turns out i misslead you but i honestly thought it would work

Mactronix
a c 169 U Graphics card
April 27, 2009 10:43:43 AM

From what i know,the cards have to be exactly the same model,i did some google search and it seems that u can'T SLI them unless u flash the BIOS of a 8800GT:

http://www.overclock.net/nvidia/405009-sli-9800gt-8800g...
"You can't run them in SLi due to the different BIOS's on the cards. You might be able to flash your card to a 9800GT BIOS but you run the risk of bricking it."

http://forums.slizone.com/index.php?showtopic=31687
"The official answer from Nvidia is NO, but people have gotten it to work via force BIOS flashing."

http://forums.guru3d.com/showthread.php?t=279154
"Has anyone tried putting them directly into SLI without a BIOS flash? I know the answer is 99.99% likely to be yes but I had to ask anyway.

Also, they have the same core, RAM and clock speeds but are the memory timings the same between the two?

They will not work without a BIOS flash, search for threads if you want proof.

Also the memory is not the same on the 9 Series, it is slightly higher rated and slightly faster."
a c 130 U Graphics card
April 27, 2009 11:21:21 AM

As i said i know you know what you are talking about its just so stupid that you cant, Nvidia don't actually say you cant do it they just say you should use two identical cards for Optimal performance.
Also the Bios shouldn't matter as they say after the release 80 drivers you can mix Manufacturers which to me means different, or the possibility of a different Bios. I do know of at least one card that i looked into very deeply where different Bios versions were used.
Nvidia say you can mix a vanilla with an OC version so the ram and memory timings shouldn't matter either.
So whats the game ? Fair enough threads seem to say it needs a Flash, but it shouldn't matter.
Im just curious as to why technically they wont. My guess would be Nvidia have put something in the SLI key to stop them working specifically to stop people SLI ing the cards to try and maximise sales.

Dont get me wrong im not trying to argue im right and your wrong i just want to know why ?

Mactronix
a c 169 U Graphics card
April 27, 2009 11:33:12 AM

No mac i know what u are saying :)  no argues here we are just talking and trying to find the answer :)  and i myself am curios too,i looked @ the specs of 8800GT and 9800GT in Nvidias site and they are exactly the same,so they should SLI without a problem but after doing a google search i found that users have to flash their BIOS to make it work.
Its strange for me too because as u said u can SLI a non OC'd card (like a normal 8800GT) with an OC'd 8800GT and it doesnt need flashing(and 90% of the times the faster card will downclock to match the speeds of the other except for some rare situations that the slower card reaches its speed to the faster model)
But 9800GT and 8800GT have exactly same specs,i dont know why it needs a BIOS flash.

However if u look @ my last link(From Guru3d) u will see that the guy says "The memory is not the same on 9 series,its slightly higher rated and slightly faster."

This maybe the reason but what memory he is talking about ?(Because the Memory clock of both cards is the same)
a c 130 U Graphics card
April 27, 2009 12:38:10 PM

Looks like i was onto something.
If this thread is correct then there is a hardcoded device ID in the BIOS. I dont ususlly put much store in other forum posts as you dont know who actually knows stuff and whos blowing out of their... Well you know what i mean :D 
http://www.mvktech.net/component/option,com_joomlaboard...

Mactronix :) 
a c 169 U Graphics card
April 27, 2009 1:10:46 PM

I myself dont count much on every forums :D  when i google i try to find my answers from some reliable tech sites thats why i posted from those 3 sites :D 

According to the link u gave me,the hardcoded BIOS maybe the reason.
Whats your opinion about the guy that said Memory on 9 series is higher rated and its faster ?
a c 130 U Graphics card
April 27, 2009 3:24:20 PM

I dont see that making a differance. As i said earlier Nvidia themselves say you can mix and match OC cards with standard and i know for a fact that some OC cards use differant memory from standard.
The hardcoded bios makes most sense to me given that people are basically saying that differant G92 powered cards will only play right when you have the same bios on each card.

Mactronix
a b U Graphics card
April 27, 2009 4:24:03 PM

I'd flash the 8800GT BIOS to a 9800GT BIOS, but theres no real reason why not.
a c 169 U Graphics card
April 27, 2009 4:27:42 PM

mactronix said:
I dont see that making a differance. As i said earlier Nvidia themselves say you can mix and match OC cards with standard and i know for a fact that some OC cards use differant memory from standard.
The hardcoded bios makes most sense to me given that people are basically saying that differant G92 powered cards will only play right when you have the same bios on each card.

Mactronix


Yeah thats the most reasonable thing to accept this.
May 13, 2009 4:50:14 AM

Hey!

Thanks guys for all your help. It was just a thought since I wasnt able to get a similar 8800GT. Guess if you plan to do SLI you should buy both cards at the same time! Otherwise you become the victim of obsolescence. Anyay I was doing lot of hardware research because my Asus p5n32 Esli mobo was giving me problems, machine wouldnt post. It took me lot of time to figure out it was the mobo problem and not RAM, SMPs etc and finally got a Gigabyte mobo. Anyway since i was thinking about hardware upgrades this thought struck me cos i heard both were almost identical chipsets. Thanks for all the enthusiastic replies!
a c 169 U Graphics card
May 13, 2009 10:58:39 AM

No problem mate :) 
!