Crossfire question

[TOAOCyrus]

Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

 

[batmang]

To use CrossFire the two cards must have the same exact GPU/model. So unfortunately, that wont work. You have to have two of the same kind to utilize CrossFire.

 

[Nurn]

Originally posted by: batmang
To use CrossFire the two cards must have the same exact GPU/model. So unfortunately, that wont work. You have to have two of the same kind to utilize CrossFire.

Not quite true. For example you can run a 3850 with a 3870 in crossfire. Check out the ATI Compatability Chart (although it is not really too clear in my opinion).

http://ati.amd.com/technology/crossfire/charts.html

In fact, these guys got a 3870 and a 2900 to work in crossfire.....

http://xtreview.com/addcomment...HD-3870-Crossfire.html

 

[batmang]

Whoa, I wasn't aware of that. My mistake!

 

[TOAOCyrus]

Hmm I guess Ill have to expirement then.

 

[NinjaJedi]

Originally posted by: Nurn

Originally posted by: batmang
To use CrossFire the two cards must have the same exact GPU/model. So unfortunately, that wont work. You have to have two of the same kind to utilize CrossFire.

Not quite true. For example you can run a 3850 with a 3870 in crossfire. Check out the ATI Compatability Chart (although it is not really too clear in my opinion).

http://ati.amd.com/technology/crossfire/charts.html

In fact, these guys got a 3870 and a 2900 to work in crossfire.....

http://xtreview.com/addcomment...HD-3870-Crossfire.html

I remember reading that you can also put a 3870x2 with a 3870 and run a crossfire also. Not sure if you can put a 3870x2 with a 3850 but maybe.

 

[heyheybooboo]

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

No way it will work ....

How much you want for that 2900pro ??

 

[TOAOCyrus]

Originally posted by: heyheybooboo

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

No way it will work ....

How much you want for that 2900pro ??

Im going to give it a try first before selling it

 

[BFG10K]

The 3870 X2 is already Crossfired internally so by adding a 2900 Pro you're essentially asking for tri-Crossfire.

There's not even a driver for that yet.

 

[apoppin]

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

*impossible*

who cares what we think ... i USED to think it would work

http://ati.amd.com/technology/crossfire/charts.html

you can only Xfire 2900Pro with 2900XT or another Pro ... what i am doing

now WtF is "Internal CrossFire Interconnect"
-do i or do i NOT need 2 interconnect bridges?


i believe i do ... at least i just ordered another one from NewEgg 1/2 hour ago- --save me money

 

[Sylvanas]

Originally posted by: Nurn

Originally posted by: batmang
To use CrossFire the two cards must have the same exact GPU/model. So unfortunately, that wont work. You have to have two of the same kind to utilize CrossFire.

Not quite true. For example you can run a 3850 with a 3870 in crossfire. Check out the ATI Compatability Chart (although it is not really too clear in my opinion).

http://ati.amd.com/technology/crossfire/charts.html

In fact, these guys got a 3870 and a 2900 to work in crossfire.....

http://xtreview.com/addcomment...HD-3870-Crossfire.html

Yes you can Crossfire a 3850 and a 70 because theyre both essentially the exact same architecture (RV670) the only thing is if you have say a 512mb 3870 and a 256mb 3850, the 3870 will be scaled back to a 256mb frame buffer to work with the 3850- at least this is the general assumption.

I used that link here a while back but on further investigation I found This and this which tends to point to the fact that the 2900 and 38 series were not *really* designed to work together in X-fire, Driverheaven seem to get it to work though, as have some other users so the jury is still out on this, it will be good to revisit this subject once we get the CrossfireX drivers most likely in the 8.3 release.

 

[Sylvanas]

Originally posted by: apoppin

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

*impossible*

who cares what we think ... i USED to think it would work

http://ati.amd.com/technology/crossfire/charts.html

you can only Xfire 2900Pro with 2900XT or another Pro ... what i am doing

now WtF is "Internal CrossFire Interconnect"
-do i or do i NOT need 2 interconnect bridges?


i believe i do ... at least i just ordered another one from NewEgg 1/2 hour ago- --save me money

I don't think you NEED two for it work but i think its 'better' if it does, google the subject there are plenty of threads around- last I remember was the consensus was that there 'may' be more bandwidth being utilized with two bridges + less problems with 2 bridges, so I'd stick with using two. I have two on my 3850's and its been great since day 1 (you should get a Crossfire bridge with each card so you sure you need to order one? ).

 

[apoppin]

Originally posted by: Sylvanas

Originally posted by: apoppin

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

*impossible*

who cares what we think ... i USED to think it would work

http://ati.amd.com/technology/crossfire/charts.html

you can only Xfire 2900Pro with 2900XT or another Pro ... what i am doing

now WtF is "Internal CrossFire Interconnect"
-do i or do i NOT need 2 interconnect bridges?


i believe i do ... at least i just ordered another one from NewEgg 1/2 hour ago- --save me money

I don't think you NEED two for it work but i think its 'better' if it does, google the subject there are plenty of threads around- last I remember was the consensus was that there 'may' be more bandwidth being utilized with two bridges + less problems with 2 bridges, so I'd stick with using two. I have two on my 3850's and its been great since day 1 (you should get a Crossfire bridge with each card so you sure you need to order one? ).

i know i *should* get a Xfire bridge with *each* card but you gotta know Sapphire is a "cheapass" company - i would never buy a Sapphire unless it was covered by a REAL warranty - like NewEgg's 1-year exchange

really? ... just one ... i thought those threads were 'iffy'


well, then .... i will try it as soon as i finish Part One of my Vista testing - today[!] - i can always *refuse* newegg's bridge interconnect package if i run into problems so i don't have an extra restocking fee ... naturally, if it works OK [somewhat - and i am thinking about "PS" and "heat" isues] i will install the 2nd one on Tuesday [in 10 seconds]

i *know* mine is a "budget" 'mickey-mouse' CrossFire [2900xt512M/512bit with 2900p/512M/256bit] .... for ~150 ... or $500 total for both cards - i just want to see if i can beat Ultra performance for a really cheap and 'quick 'n dirty' upgrade
-and that Pro *better* OC

 

[bryanW1995]

sli requires the same exact card, crossfire doesn't. As long as you have driver support you'll be able to crossfire the 3870x2 with a 2900. You are actually running tri-fire with the x2 and 2900, however, and they don't have driver support for that yet. it's supposed to be out in late feb/mar time frame.

 

[apoppin]

Originally posted by: bryanW1995
sli requires the same exact card, crossfire doesn't. As long as you have driver support you'll be able to crossfire the 3870x2 with a 2900. You are actually running tri-fire with the x2 and 2900, however, and they don't have driver support for that yet. it's supposed to be out in late feb/mar time frame.

not according to AMD
-the 2900GT is the one 'next' to be supported


http://ati.amd.com/technology/crossfire/charts.html

of course, i am sure it can be done ... you like driver hacks?

 

[heyheybooboo]

Originally posted by: Sylvanas

Originally posted by: apoppin

Originally posted by: TOAOCyrus
Hey I just ordered a 3870X2 to replace my 2900pro. Is it possible to put them tegether in crossfire and would there be any performance boost? I can OC my PRO to 825 MHz so they would match. What do you guys think?

*impossible*

who cares what we think ... i USED to think it would work

http://ati.amd.com/technology/crossfire/charts.html

you can only Xfire 2900Pro with 2900XT or another Pro ... what i am doing

now WtF is "Internal CrossFire Interconnect"
-do i or do i NOT need 2 interconnect bridges?


i believe i do ... at least i just ordered another one from NewEgg 1/2 hour ago- --save me money

I don't think you NEED two for it work but i think its 'better' if it does, google the subject there are plenty of threads around- last I remember was the consensus was that there 'may' be more bandwidth being utilized with two bridges + less problems with 2 bridges, so I'd stick with using two. I have two on my 3850's and its been great since day 1 (you should get a Crossfire bridge with each card so you sure you need to order one? ).

So let's say I have two 2900's in Crossfire. You're saying that it's okay to 'double-bridge' between the two cards ? That's good news ...

I didn't know - I'm new to this Crossfire thang - I was looking at the card and trying to figure out which one of the two interconnects I would use - lol

 

[apoppin]

So let's say I have two 2900's in Crossfire. You're saying that it's okay to 'double-bridge' between the two cards ? That's good news ...

OK? ... it is the recommended way to go


and it's "good news" Only if you already have 2 interconnects ... i had to buy the 2nd one because Sapphire is too G-damn cheap to include it with their 2900pro - unlike VT
--Sapphire sucks Big donkey dongles. :|