Overclocking issues 5850

[grahamie]

Im having issues with overclocking my xfx reference 5850 BE i have a matching pair one i bought new and one used . When i separate the cards and overclock them individually i have great success with the card i bought new on the other hand the used card i cant change the gpu or the ram when i up the gpu i get tarring and flashing even when idle in windows and i cant touch the ram at all ive suffered a few bsod`s in this process
now at stock clocks the cards run fine alone and in crossfire getting consistent benchmarks and good numbers with no bsod`s
i thought maybe i had a heat issue with the ram on the used card so ive now liquid cooled both cards and i have good temps so heat is not an issue. Drivers also are not the issue as ive tested all drivers from 10.7 up to 11.4 using clean install methods
does any one have any ideas what the issue could be so I have a good reason to rma a obviously damaged but not broken card

 

[COLGeek]

What make/model of power supply are you using and how are your temps running when both are installed?

 

[grahamie]

bought about a year ago silverstone strider 1000w bronze psu that has been tested and temps are 34c idle and 50c max for both cards

 

[COLGeek]

Are they both on the same version of firmware?

 

[grahamie]

all numbers are matching in CCC and RBE

 

[COLGeek]

Are you OCing the CPU or memory?

 

[grahamie]

Yes im overclocked on cpu, memory, n/b, h/t
but i get the same result with all default settings

 

[COLGeek]

That is what I was wondering, if it did the same at default speeds. It may simply be that your config is at its limit regarding OCing the GPUs reliably. I am at a loss with this one.

When you OCed them individually, how hard could you push them?

 

[grahamie]

the new card overclocks to 1000 1300 and the used card clocks 770 1125 and the default clocks are 765 1125
both cards run unigine heaven with out an issue at thoes clocks but not above

Im also at a loss and it sucks because overclocking one card in xfire is useless from what i understand

 

[COLGeek]

Right, OCing one GPU is meaningless as the 2 are synched at the least common denominator. Still they are faster than a single OCed GPU having 2 stocks GPUs in CF.

It may be that the used card was over cooked in its previous life and it just can go up there anymore. OCing anything adds risk.

 

[grahamie]

i guess im going to have to try and rma the old card and keep my fingers crossed thank god for xfx 2x life time warranty

 

[COLGeek]

Good luck on the RMA!