SLI / CrossFire FAQs

[Maziar]

Download GPU-Z and see if it says CrossFire is enabled or not

 

[obriza]

I am thinking of going for a crossfire setup on my current mobo, but it only has one x16 and one x8 so im guessing it would be pointless going for a big card as alot of the speed will be lost in the x8 configuration? any recommendations on which cards will best suit this config? or will it maybe be better to just go for one big x16 card?

 

[Maziar]

You will see a performance hit when you use CrossFire @ dual 8x mode.
Please post your system specifications and we can help you more.

 

[obriza]

my current system is
G-B-EP45-DS4P
Q6600 might be upgrading to Q9550or9650
G.Skill-PI 4GB DDR2 1066
PSU im thinking of going for Coolermaster RealPower Pro 850w if more needed can go to the 1kw version
also have Asus D2X soundcard if it makes a difference
and coolermaster 1100s case
everything is standard clock too

 

[Maziar]

And what resolution will you play at ?

 

[obriza]

i usually play at the highest i can

 

[Maziar]

What it is ? 1280x1024 ? 1600x1200 ? or higher ?

 

[-713king-]

if i have a p6t motherboard and has 3-Way SLI & Quad-GPU CrossFireX Support! .. the CrossfireX does that mean i can only crossfire with a card that is like HD 4XXX x2 or what? or i can just do the normal crossfire

 

[obriza]

well right now im using 1360 x 768 or 1280 x 1024

 

[Maziar]

if i have a p6t motherboard and has 3-Way SLI & Quad-GPU CrossFireX Support! .. the CrossfireX does that mean i can only crossfire with a card that is like HD 4XXX x2 or what? or i can just do the normal crossfire

If your motherboard supports CrossFireX,then it supports all kind of CrossFire,here is an example:
ATI HD 4870 + ATI HD 4870 (2-Way CrossFire)
3xATI HD 4870(3-Way)
4xATI HD 4870(4-Way)

 

[Maziar]

well right now im using 1360 x 768 or 1280 x 1024

That resolution doesn't need either CrossFire/SLI, a fast single card will be more than enough.

 

[Mharka]

[No message]

 

[-713king-]

thank you maziar i was confused lol well im getting my video card tomorrow! HD 4890 by sapphire vapor-X technology i can finally have my rig finished!

 

[Maziar]

No problem mate glad you find it useful

 

[ac3144]

Evening Maz,
I thought you may know the answer to this (font of all GPU knowledge an' all) to put it to bed so to speak...

What is the official position on CF bridges? One or Two?
The advice is conflicting, just wondered what ATI say? Any ideas/
There is another thread on this topic and everybody is saying different things (me included):
http://www.tomshardware.co.uk/forum/page-265538_15_0.html
Cheers
AC

 

[liknat]

Maziar, i have been thinking about the same thing as ac3144 above. You should add this bridge info to the already superb FAQ when it is settled.

By my information, I watched the official amd/ati promotional video

http://game.amd.com/us-en/unlock_sevenseries.aspx

(follow the red demo link - watch the whole thing or skip to superior scalability)

and it shows clearly that you have to only use one bridge per 2 cards even if you have 2 places to put it on the card.

nukemaster, can you tell me where I can get/buy/which MB manufactures have longer Crossfire bridge cables? I am planning a major upgrade and will be needing longer ones for sure.

 

[Maziar]

Well i did a Google search and found some results:
http://www.tomshardware.com/forum/251878-33-crossfire-bridges
http://www.tomshardware.com/forum/254618-33-crossfire-connectors
http://www.xtremesystems.org/forums/showthread.php?t=202120
http://www.overclock.net/ati/517132-crossfire-bridge-install-both-one.html
http://forums.whirlpool.net.au/forum-replies-archive.cfm/1101088.html

As you see all of them says that for 2 Cards in CrossFire,a single bridge suffices but you can use 2 bridges as well and with using 2 bridges you won't lose either of the bridges,also there are some reports of "Minimal" FPS increase.

Taken from those links:
"only NEED one - but i think 2 looks better - you can get up to 3FPS better with both on - but a very small difference"

"i tested it out and the other post was right.you only need one bridge for two cards.my 3dmark06 score with one was 18128 and with two it was 18058.dont know why it dropped probably just slight changes with system performance.12500 one 3870,18100 in crossfire"

So as you see 1 bridge is fine but its better to use 2 bridges.

But thanks for mentioning this i will add this info in the first page

 

[Maziar]

Edited with some new info's.

 

[xtechcor]

Hi im new to this site and i was searching almost everywhere. I got a question about Hybrid SLI and a onboard memory question.

First of all can anybody of you please help me to find a benchmark or something that will show how a GF8100VM-M3 with a 8100 onboard runs with a 8500GT in Geforce boost? and is Geforce boost any good at all in a good boost in performance?

My second question, if i go and play a game with say 512mb shared memory... and my memory speed is 800mhz. then the memory for the onboard graphics will be 800mhz? i dont know if this is true, thats why i came to ask you guys cause i cant find a answer to it. and if I say upgrade my system memory to 1066mhz, will my onboard graphics improve? cause it is shared after all.

2GB DDR2 800mhz
AM2 4200+ 2.2GHZ
GF8100VM-M3

 

[nukemaster]

For the crossfire bridge, Any board that has 2 other slots between its PCI-E slots used to need a longer bridge(Mostly when SLI came out), but it looks like ATI's current line of bridges are flexible and work for PCI-E slots 0(Single slot cards),1 and 2 slots apart.

It clearly reaches far enough and since its flexible it will work in shorter distances as well. I think you will be good to go with what ATI includes with there higher end cards. If you need more, Ebay has a bunch.

 

[Maziar]

Hi im new to this site and i was searching almost everywhere. I got a question about Hybrid SLI and a onboard memory question.

First of all can anybody of you please help me to find a benchmark or something that will show how a GF8100VM-M3 with a 8100 onboard runs with a 8500GT in Geforce boost? and is Geforce boost any good at all in a good boost in performance?

My second question, if i go and play a game with say 512mb shared memory... and my memory speed is 800mhz. then the memory for the onboard graphics will be 800mhz? i dont know if this is true, thats why i came to ask you guys cause i cant find a answer to it. and if I say upgrade my system memory to 1066mhz, will my onboard graphics improve? cause it is shared after all.

2GB DDR2 800mhz
AM2 4200+ 2.2GHZ
GF8100VM-M3

Hello and welcome to the forums mate

About your first question,you will barely see an difference because Hybrid SLI is mainly for power savings.... and it doesn't improve performance much.
"SLI" will give users a boost in their gaming experience and "Hybrid SLI" as i said is mostly for power savings.
Also unfortunately a 8500GT isn't a good card for gaming so even if you get another 8500GT and SLI it it won't perform well,if u want to game then you have to change your VGA.

About your second question,don't mix up things with each other because VGA and RAM don't have any effects on each other,your card is a 8500GT 512 and your RAM is a DDR2 800 model,they work apart from each,so RAM doesn't change the VGA speed or viceversa

 

[xtechcor]

You misunderstood...

I dont got a 8500GT all i wanted to was... Is the system memory your using for your onboard? Is it the same memory speed as your system memory? In my case i got 800mhz, now that its shared. Will my onboard run better if i upgrade to 1066mhz? thanks for your answers..

 

[Maziar]

Sorry mate i don't understand well,do you mean upgrading your 800MHZ memory to a 1066MHZ one boost the speed of onboard memory ? if that's what you are asking then the answer is no

 

[xtechcor]

Cool thanks,then can you maybe tell me where i can go for it to show me the onboard memory speed? CPU-Z,Latest Everest dont show anything just the core clock and the shader clock, but not the memory speed nor the type of memory or bandwidth...Can anybody maybe help me to correct me where i can look for this?

 

[meodowla]

1920x1200 is one of the resolutions that benefit from multiGPU in most games.

What about 1920x1080?