Welcome to MilkyWay@home

Multi-GPU Question

Message boards : Number crunching : Multi-GPU Question
Message board moderation

To post messages, you must log in.

AuthorMessage
Profile Dan Holtz
Avatar

Send message
Joined: 27 Sep 10
Posts: 12
Credit: 36,554,546
RAC: 0
Message 53535 - Posted: 4 Mar 2012, 3:34:17 UTC
Last modified: 4 Mar 2012, 3:51:16 UTC

OK, here is what I know:
If I crossfire a HD5850 and a HD5870 the 5870 will downclock itself to the 5850's GPU and Memory clock settings.

Now here is the question:
If I put 2-5850's in slot 1 and 2 and crossfire them and then place a 5870 in slot 3 without a installing a crossfire bridge will the 5870 still downclock?

I want the 5870 at full speed and the 5850's have enough horsepower for my gaming when crossfired. So the output from the 5870 is not needed for driving a display.

Question comes up because XFX just did a warranty swap on a HD5850 Black Edition on me and sent a HD5870 as the replacement. I was running 3-5850's crossfired but I sure would love the boost the 5870 should be able to provide.

Thanks
ID: 53535 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Zydor
Avatar

Send message
Joined: 24 Feb 09
Posts: 620
Credit: 100,587,625
RAC: 0
Message 53537 - Posted: 4 Mar 2012, 8:49:46 UTC
Last modified: 4 Mar 2012, 9:00:49 UTC

If I put 2-5850's in slot 1 and 2 and crossfire them and then place a 5870 in slot 3 without a installing a crossfire bridge will the 5870 still downclock?

Cards without a crossfire bridge attatched are "on their own", and will not be affected by any routine crossfire driven requirement, restriction or enhancement that may (or may not) apply, to single GPU crossfired cards in the same box connected at the same time.

The above is carefully worded as there are differences between Crossfire and CrossfireX, but in the circumstances you are describing I see no issue, and a standalone card ( standalone in terms of the card not being connected by a crossfire(X) bridge) has no idea Crossfire or Crossfire(X) is there, so I cant see any problem with your hoped for effect.

Your Gamer Card(s) should at the least have one card in slot zero (attatch monitor to that one in slot zero).

There are exclusion clauses that you can put into cc_config which will tell BOINC not use various card makes and mainboard slots. The latter facility has its trips and traps - in particular the wording of the clauses and supporting explanations means what it says it means, despite human temptation to *think* it *also* means something else, so watch that - but for the most part works ok, maybe worth a look, as it may help you in your specific circumstances.

Regards
Zy
ID: 53537 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
Profile Dan Holtz
Avatar

Send message
Joined: 27 Sep 10
Posts: 12
Credit: 36,554,546
RAC: 0
Message 53540 - Posted: 4 Mar 2012, 16:58:08 UTC

Thanks for the insight on my issue. I will let the cache work it's way out for the NVIDIA 460 that took the original card's place and replace it with the 5870.

If you don't mind a little more schooling of someone who has a bit of ignorance in this area...

What is the difference between crossfire and crossfire X?

Thanks
ID: 53540 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote
[boinc.at] Nowi

Send message
Joined: 22 Mar 09
Posts: 99
Credit: 503,422,495
RAC: 0
Message 53542 - Posted: 4 Mar 2012, 21:20:54 UTC

For a first information look here: http://en.wikipedia.org/wiki/AMD_CrossFireX
ID: 53542 · Rating: 0 · rate: Rate + / Rate - Report as offensive     Reply Quote

Message boards : Number crunching : Multi-GPU Question

©2024 Astroinformatics Group