On my PALIT overclock +135 core + 300 mem ccminer 0.5 its ok .
On my MSI overclock +175 core + 550 mem ccminer 0.5 after 6 hours CRASH .
Now try +150 core + 500 mem on MSI .
On my 2 x 750 Ti MSI gaming +250 core +550 mem 9 hours no crash. (~26mh/s on HVC for both)
Could do that on 2 x 750Ti,but will be crashed with 6 cards,i did it.Stable with 220 core and 500 mem