ATI Gigabyte HD 6870 and Sapphire R9 290 working together

edited January 2014 in Hardware

Hi! I'm mining with a GPU R9 290 very good in my system, using SMOS-Linux 1.3 from an usb stick.
I'm wondering if my PSU is going to support another card.

I've made the calculations in PSU Calcs and they say that is going to work nice.

My System:
Gigabyte Z68
Intel i7 2700k
16GB Ram DDR3
Cooler Master Extreme Power Plus 700w
Sapphire R9 290 BF4 Edition.

I get that the computer is going to consume 600w approximately (without using CPU too much, only mining and without HDDs).

Do you think that is going to work fine if I add my old GPU card 6870? I'd like to have some extra (300~KHash) in my mining pc.

Thanks a lot for your help,



  • Try to find the power consumption specs for each card on the manufacturer's website ... not always easy.  Sometimes they talk about what power supply you need for the whole system with 1 card.  That doesn't help you.  You need to know what each card can draw.  Add the peak consumption of all gpu's and about 200 W for the rest of your system.  In this thread, I talk about how to find out how much power you PC IS using.  Predicting what it will use is harder.



  • I'm using a R280x and a hd7950 on a 750W PSU.
    Full rig (mobo, fans, GPU) use 580W, but was 680W before optimizations:
    - I'm using Bamt on USB disk (need less power than HDD)
    - reduce max power per cards by modifyng bios. I've use VBE7 to lower TDP from 233W to 200W.
    - I disable all unuse on mobo in computer bios, like usb3, RAID controler, IDE, floppy controler, ..
    - My mobo as a "power green" option, that I enabled. It reduce CPU power when CPU is not use.
    - unplug USB keyboard.
    - dont increase 'powertune' in cgminer. Try to lower it a bit

  • edited February 2014

    Very smart and usefull post vikingfr

    A lot of people ask if this PSU will be enough for this system. Then they start to overclock gpu like hell while staying at factory voltage and they are surprised to run into problems.

    I believe that undervolting gpu is the measure with the biggest potential power consumption decrease.

    For example, i have a PC mining with a 280x running on a Antec 430 W PSU. The idea was to plug the card in an existing PC and do no more expense, that's why. The card run at 870 Mhz and 980 mV. Sure,it produces only 630 kh, but very stable and the PC stays rather silent and can still be used for other tasks, and the PSU doesn't blow. It works perfectly, while most people will tell you that its impossible to run a 280x on so small a PSU.

    The consumption of a GPU depends on intensity, core freq and core voltage, mostly. If you decrease Intensity, you lose much hashrate. If you decrease core freq, you lose hashrate but not so sharply. If you reduce voltage, you lose nothing (as long as it doesn't produce instability, rejects or HW errors : you should check for that). What do you conclude ?

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