They are 4/3/2/1 GB. All of them can mine XMR because its not memory size bound in terms of the DAG in ETH.

When you use multiple power supplys then you have current from one 12V rail to another because the rails are not exact the same voltage on both psu. If you power riser and GPU from different PSU then in the worst case this generates heat at the wrong place because of the differential voltage and the short-circuit current. You can measure this with a multimeter connected to the different 12V rails.

This multi PSU setups could be safe, they are probably safe if properly distributed.

SATA to PCIE 6 Pin adapter have another problem. Fake chinese wires and no proper clamping in the SATA connector... They claim to be AWG18 but they are thin as f... I only use PCIE to 4 Pin Molex and test one adapter of each bulk order by destroying it and checking the diameter of the wire.

cheap gpus for xmr? the complete AMD GCN 1.0/2.0 bouquet:

7850, 7870, 7870XT, 7950, 7970, 7990
R7 265, R9 270, R9 270X, R9 280, R9 280X, R9 285 (gcn 3 but doesn't matter), R9 290, R9 290X
R7 370X, R9 380, R9 390, R9 390X

they do all over 420 Sol/s, the bigger ones even up to 900.

Have two timings for hynix from russian board, maybe you can try this:

Hynix; The most stable in frequency. 1167 / 1980-2070. ETH = 28.5-29.4 MH / s.

777000000000000022C39C00AC595A3D90550F12B84C8408004006007E0514206A8900A00200312 0100F292F94273116

Made on the basis of 1. But slightly weakened timings. This gives + 50-80 MHz. At the same frequency, the loss is 0.2-0.3 Mach. At +50 wins + 0.2-0.3. +80 = 0.5-0.6. Frequencies 2050-2150.

999000000000000022C39C00AC595A3D90550F123CCF530C004006007E0514206A8900A00200312 0100F292F94273116

source: https://forum.bits.media

good luck!

Step for step guide:

Download AMD Blockchain driver or adrenalin driver (you have to set to compute mode)

Mod your driver with
https://www.monitortests.com/forum/Thread-AMD-ATI-Pixel-Clock-Patcher
so it accepts modded bios

Download bios from your card with atiflash 2.77

Modify it with https://github.com/jaschaknack/PolarisBiosEditor
Use one click timings if in doubt

Reflash your card with atiflash and the modded bios

Reboot

Enjoy 28-32 MH/s

please use this

https://www.monitortests.com/atikmdag-patcher-1.4.6.zip

then your driver accepts modded bios

I have the exact same behaviour with my two rx580 sapphire pulse, 8 gb, micron memory

I get them to 770 h/s @ 1200 Core, 2000 Mem, but even with 1411 Core and 2150 Mem they won't be faster!

are you serious?  I tested my suggestion and it worked, modifications are also applied if done properly.

try this one: https://github.com/jaschaknack/PolarisBiosEditor

Not planning to overvolt but especially the Nvidias can go 120% PT and e.g. the 1080ti can do 2050 Mhz+

Hi,

I read the other "how long will they last" thread and I've a similar but different question:

My noisy GPUs are all on water with a monster radiator (Phobya Supernova 1260 / 4x 200mm Fans) so they chill around 45° C all the time with max OC. The question: is it safe to OC / Max out the Powertarget 24/7 without increasing the voltage?

Sapphire RX480 Nitro+ OC 8 GB (ETH)
Zotac 1080ti (ZEC)
Gigabyte 1070 itx (ZEC)
VTX R9 290 (ETH)

and a XEON 1660 (Hexacore) for XMR

Efficiency is not a question for me!

PSU are Tier 1 ones with lot of headroom!

Looking for interesting answers / discussion

try to connect a display to the cards, at least one display or dummy hdmi plug.

I can't tell you THE correct way but I can tell you the way it works for me (with much more expensive cards, eg 1080ti)

One Power Supply for the CPU+MB (~300W)

Then more Power Supplys to power the Cards AND the Risers (same Power Supply for Card and corresponding Riser). So there is only data connection between the two PSU, no VCC so no difference current between two different 12V rails. That much caution may not be needed but I'm driving safe.

please upload stock bios (silent and turbo)

rumours say that the special edition has overclocked memory and I think they relaxed the timings due to high ecc error rate incoming

reinstall pixel patcher after inserting second card, original driver seems to reinstall after card modification

disable crossfire for mining, always!

you can crank the voltage up a little bit (10%) but with these cards i think there is no hope for good earnings unless you have free power.

also take care of temperature, my cards are ALWAYS under 70° celsius, but I target 60° for better durability.

so fan speed ALWAYS 100%

install fglrx driver, while amdgpu (pro) work for gcn 1 cards, opencl wont!

If you're in a hurry, install ubuntu 14.04 and proprietary fglrx drivers through ubuntu additional drivers utility.

Hi folks,

I often read that you should drive your GPUs at 80% TDP for durability reasons.

Because I am in a "no noise allowed" space, I did watercooling long ago, costed me $80 for each GPU extra + one time investment of ~350$.

GPUs are still at 80% TDP but not exceeding 40° Celsius, especially the 1080ti's and the 1070 are cold as ice .

Would you crank up the TDP or are there still durability concerns?

Regards

as requested:

original 4gb sapphire pulse itx rx560 bios:
http://www104.zippyshare.com/v/Pz1dZOOx/file.html

my mod bios:
http://www104.zippyshare.com/v/8A1XuXKV/file.html

I modded the bios successfully and increased the mining speed to ~14.xxx mh/s with the following settings:

bios mod:

1750 timings -> 1875, 2000
max memory clock 2000 -> 2200

amd radeon settings:

gpu clock -> 1125 (underclock)
memory clock -> 2000
fan -> 100%

ASIC is 65% and 75% so they run 60° and 53°. Memory is Micron 4GB.
Could push the memory clock further now but I'm satisfied and let them work for 48h.

I think they could do 15.xxx mh/s but with much more power draw and heat dissipation.

And disable crossfire in amd tool, enabled by default!