Unstable memory when overclocked on Sapphire Radeon 6850 vapor_x 1x6-pin

Antonix21

Honorable
Apr 13, 2013
2
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10,510
I have overclocked my sapphire radeon 6850 vapor-x : GPU:1000Mhz , Memory 4500Mhz , VDDC:1250
If I increase the GPU voltage to 1251 it crashes.
When I play a game whit this settings it is ok, but if I increase memory clock to 4600Mhz effective (1150Mhz) I start to se artefacts and the picture on the screen is not calibrated to the screen, parts of screen are black and in-game textures are not full. I set the core clock to 775Mhz which is standard for this card and increased memory to 4600Mhz but it is still the same. I am confused because I have seen people on other sites to overclock the memory to 5200Mhz. They all had an 2x6-pin version. Is the lack of power that causes poor memory OC.
 

PritishPrayag

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Apr 12, 2013
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10,520
the HD6850 vapor-x comes with an overclock outta box. And the folks at Sapphire must have tried to get the best OC at stable temp. So further OC is not tangible and doesn't give any good performance per watt.
Pretty evident from your results that your overclock is not stable.
Considering your case, I believe you haven't performed a bechmark test as soon as you completed the OC. if you see any artefacts, the process is not going good, underclock and again benchmark. So, try to settle at around 790-800/1.09-1.1GHz for core and memory clock respectively.
:rockon:
 

Antonix21

Honorable
Apr 13, 2013
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10,510
tnx. I have run some tests and I found 980Mhz GPU and 4560Mhz memory effective to be stable.
Now I am thinking to put another one into crossfire since then I would have around 9000 3DMARK 11 points.

 

PritishPrayag

Honorable
Apr 12, 2013
16
0
10,520

Dude adding an additional HD6850 won't provide tangible scaling, I recommend you to save money and buy a single more powerful newer gen Graphics card. Like an HD7870 or GTX660Ti.
:) :bounce: