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VDDC Current for 7870XT overclocked?

post #1 of 6
Thread Starter 
What is a safe current for the 7870XT's. I'm currently mining with them, undervolted to 1.075 and clocked at 825/1765. They run pretty stable, but I'm sort of worried by the VDDC Current reading: it reads 76A and sometimes jumps to 125A. Is this safe, or am I in immediate danger?

Edit: For reference, stock voltage with 800core clock and 1500mem clock, reads 95A...
Edited by JohnyR - 12/31/13 at 4:35pm
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post #2 of 6
Hmm that is a good question and I never considered the implications of having a much higher current when undervolting the card. I suppose it depends on the PCB design of the card and what power delivery system the card has. However even with a bump of volts to 1.2V I don't see the card using less than 115A max load which isn't a massive world of difference. I would hazard a guess that due to the high power nature of graphics cards with the low volts we have today that the card should be good for quite a few more amps over 125A.

Don't quote me on any of this but I'm just making logical assumptions.
post #3 of 6
I also have the 7870xt Myst and 7870xt EZ Powercolor tahiti cards
I'm interested what your hash rates are. Are you mining scrypt?

I'm undervolted mining at:

CARD 1(MYST): 0.875 volt (main display card)@800mhz clock and stock memory 1500mhz and get around 330khash/s
gpuz vddc reads between 41-43A

CARD 2(EZ) at 0.850v @793mhz clock also stock memory I get around 380-400khash/s
gpuz vddc reads between 47-49A

So cards are sipping power. should be a decent hash ratio/watt better than regular 7870 and 7950/7970 which can do better hash but use more power.
Edited by MrMaxout - 1/4/14 at 3:55am
post #4 of 6
2v? biggrin.gif

i kid, i kid
 
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post #5 of 6
Thread Starter 
Quote:
Originally Posted by MrMaxout View Post

I also have the 7870xt Myst and 7870xt EZ Powercolor tahiti cards
I'm interested what your hash rates are. Are you mining scrypt?

I'm undervolted mining at:

CARD 1(MYST): 0.875 volt (main display card)@800mhz clock and stock memory 1500mhz and get around 330khash/s
gpuz vddc reads between 41-43A

CARD 2(EZ) at 0.850v @793mhz clock also stock memory I get around 380-400khash/s
gpuz vddc reads between 47-49A

So cards are sipping power. should be a decent hash ratio/watt better than regular 7870 and 7950/7970 which can do better hash but use more power.

Cool thanks. Yeah I'm mining scrypt. My cards are at 800/1500 @ 1.075 and they're hitting 400kh/s. Really funky TC setting, 26944 but that's how I can achieve the 400kh/s
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post #6 of 6
TC of 16576 with intensity 18-19 (20 too many stales) works very well between 791-795 mhz(793 i think is optimal for my card) and like i said underclocked to .850v (slave card, a touch higher for main display card) is good for power consumption too. Also notice how fast the shares are going up sometimes i get WAY faster share rate at 18 intensity than 19 with less errors. I noticed if i crank the freq above 800mhz share rate goes down

repped you for sharing your settings to a fellow 7870tahiti owner biggrin.gif
Edited by MrMaxout - 1/8/14 at 12:47am
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