Topic: [GAMING] Can a HD 5770 and HD 5870 be CrossFired? (Read 3797 times)

if the first two numbers are the same you can crossfire them- i think the 5770 and 6770 are just rebranded cards so that makes sense.

For video cards the amps on the +12v rail(s) is most important since that's the one tehy draw their power from. That 34A number has to be a psu total reqirement, even if the 6950 was to draw it's full 220 watts it's draw is only 18.3333(333) amps. watts are simply a measure of voltage times amperage. Now, taking the time to look up the tdp of the 6950 tells me it's Board power is 200w. That is the number generally used here when looking into power supplies because pulling much more than that can have some rather detriemental effects (on that note managing to overclock to a point you pull more than that without crashing one way or another should be Nearly impossible)

So if you want a system with 3 6950 you need 600w on the +12v rail(s) or 50 amps. Single rail psu's are prefered because they eliminate several varilables in this situation those being
1 distribution between rails (ex 3 rails at 12 24 24 amps for a total of 60 amps)
2 Actual load across the entire system (loading one rail completely and leaving another empty would have a negative impact on the total efficency of the system)

Thanks for the awesome info guys!  I'm going to play around with it a little bit.

The HD6950 2GB card is 220W because:
a.unlocked it's shaders (adds 20W more power use)
b.Overclocked the card to 906MHz clock
c.Overvolted from 1100mV to 1105mV as that's the minimum necessary to keep my system stable (adds another 10W from 895MHz stock voltage)

The old Radeon Hd4670 card I used to mine wth used at most 70W due to heavy overclocking.

When people talk about running multiple GPUs in a PC,what matters more?The PSU watts it can provide?or the number of amps on the +12V line of the PSU? (As my PSU is at capaciy in the Amps section.36A max and adding my old card back would add another 26Amps and overload it,unless wattage is the bigger issue than amps.HD6950 stock requires a minimum of 34A.I found this this from somewhere but can't find the bookmarked page with that info at the moment)

at 620w i see no reason it wouldnt although i'm unsure of the power consumption of the 4670, hell i'm using an enermax 420 for a pair of 5770. as far as for 3 high end cards it depends on the card 3x5870 need 180w per card on the 12v rail 3x6970 are higher than that being dual gpu cards

Ok des,thanks for the correction.I was simply unaware of there being tri SLI setups are I was used to only seeing SLI or quad SLI.I will check those links out.I've never setup a multiGPU system before so I have no personal experience with that and also my current PSU can't cope (because the 12V line is at capacity 34A out of 36A and the remaining 2A is used by the drives) even though it's only 220W used from the 12V line and 60Ws other for my mobo and CPU,the SSD uses 0.15W when active (DVD writer use doesn't count as thats never used and consumes 20W when writing DVDs)

PSU is Enermax Liberty 620W that was bought in 2007 (April/may time I think).Do you think that PSU can handle my HD6950 card and my old HD4670 card at full load?IF not,which PSU is reliable,strong and can cope with 3 high power GPUs?

You were also wrong about triple sli not exisiting. a good resource for multi card setups is anandtech/tomshardware th did this review earlier this year
http://www.tomshardware.com/reviews/crossfire-sli-3-way-scaling,2865.html
exploring 1 2 and 3 card configurations for both sli and crossfire

I checked that guide myself as I wish to get another card at some point but not now (as PSU can't handle another card yet until suitable replacement is found).That chart only seemed to prove my point earlier about not being able to crossfire a HD 6950 (my current gpu) with say a HD6990 (the card I wish to add as an extra to my system). Yes I was wrong on my very 1st point (about same model and manufacturer) but It's a good thing that times have changed and compatitibilty is better now.My old card was a HD 4670 (which as we all know is utter crap for mining but good for most things I need to do,never had driver problems with it) and I based some of that info from other sites that were talking about the HD4xxx series cards.It's good that things are better now.I didn't know that from the HD5xxx series cards that compatibilty had improved until reading your post.

I guess it is true,you learn something new everyday.

I don't know if Im right on the modes of crossfire (2,tri-way,quad crossfire) but I do know that 2xHD6990 counts as Quad crossfire. (as each card has 2 gpus on it)
After seeing that guide,It's safe to say that I was right as the HD 5770 and HD 5830 can't be crossfired together at all (with or without the bridge connector) which should anwser the OPs question.

you can even "crossfire" an integrated card with a dedicated for some tasks, but its not called crossfire.

although i am not sure about 5k series cards, but i do know and can back up that there is greater compatibility with 6k series than 5k, although i don't know for sure,

Pretty much absolutely nothing in this post is correct.

You can most certainly crossfire cards of a different type and brand.

Here is a link to AMD's crossfire guide:

http://sites.amd.com/us/game/technology/Pages/crossfirex.aspx

Here is a link to the crossfire compatibility chart:

http://sites.amd.com/PublishingImages/Public/Graphic_Illustrations/WebBannerJPEG/AMD_CrossfireX_Chart_1618W.jpg

Nope.You can only crossfire cards of the exact same model,variant (like different ram or something) and manufacturer.

An example of Crossfire that can work is:
Sapphire Radeon HD 6950 2GB model paired with another card that's exactly the same

When you can't crossfire is in situations like this:
1 Sapphire Radeon HD 6950 2GB RAM  paired up with a Asus Radeon HD 6990 4GB RAM because the cards are very different from each other in terms of how much ram they have (variants of each card),what manufacturer they are from and what card model it is

Here is where things may get a little confusing:
1.You have a Sapphire HD 6950 2GB RAm card and you also have a Sapphire HD 6950 1GB RAM yet they won't crossfire,but why?even though its from the same manufacturer and hte same model,the only different is the variation of RAM.Some people I know got caugh tout by this.

You can also crossfire in the following configurations:
crossfire (2 way)
3 way crossfire (Nvidia cards afaik don't seem to have a triple SLI,its just SLI or Quad SLI)
and finally Quad crossfire

I hope this post answers your questions on crossfire :-)

I'm not really hip to the AMD/ATI scene when it comes to gaming so please forgive me if this is a stupid question.  But can I CrossFire a 5770 and 5870?  How about a 5770 and 5970?  Thanks in advance!