[quote name=“d3us” post=“56885” timestamp=“1391459545”]
2 different rails ;)
I’m using 6+6 pins on one rail and those molex + sata converted into 6+6 from another, so is should be enough right? :)
[/quote]

There must be something wrong with your psu. I’m using this one:
http://www.tagan.com.tw/page/datasheet/U33II/TG600_U33II_Bronze_en.pdf

first rail powers one gpu (two pci 6pin connectors) and processor (one cpu 4pin connector)
second rail powers mobo, hdd two gpus and even powered riser for the first gpu.
And i’ve got feeling that it could handle 4th card ;)
All mentioned gpus are gigabyte r9 270 ofcourse.

[quote name=“d3us” post=“56837” timestamp=“1391438478”]
My LC Power Silent Giant 6650 couldn’t manage 2x 270 OC (Core 1100, mem 1500 - 450khs, HW:0)… So 150 watts at the max load just can’t be true :S
[/quote]

according to your psu specs:
http://www.lc-power.de/index.php?id=197&L=1
It has two V12 rails rated at 25 and 27 amps.
If you are running both gpu from the same rail, it’s 25 amps, 12 volt, equals 300 watt.
Now, spec says 25 amps, but atx spec allows 5% variance, we are down to 285watt.

Did some testing, psu 80+ bronze, power measured at the wall. Mobo alone with single crappy nvidia 6200 takes 70watt
With 3x gigabyte r9 270:

idle 107watt
eco mode E949 M1400 V1.163 408kh/s each, total 510watt
nominal stock E975 E1400 V1.206 413kh/s each, total 555watt
suggested oveclock max E1050 M1500 446kh/s each, total 590watt
full throttle E1125 M1500 V1.206 464kh/s each, total 615watt

Assuming 82% psu efficiency at high load, single r9 270 uses 120watt at eco mode, 132 nominal, 142 suggested oc, 149 at max. Give or take a watt or two.

Couldn’t get the bamt smos running. Failed at the very first step - followed the instructions for windows and it simply corrupts my 2gb pendrive, its unbootable.

My system seems unstable at such high values (e1125 m1500 i19), i have to run it a bit underlocked. But i blame my psu for that, i’ve got one 30amp v12 for single gpu and another 30amp v12 for mobo, hdd and two gpu. So i can oc the first card but the two other love to crash when oc-ed.

As for the gpu temperatures i can’t imagine running it in a typical case. I’ve just finished my rig, it’s a plastic, openwork crate and gpus are sitting 10cm apart.
Gpu 2 sits on the edge and blows air towards gpu 1, it’s oc-ed e1050 m1500 fan70% temp 60C
gpu 1 is in the middle pushes air towards gpu 0, underclocked e949 m1400 fan70 temp 66C
gpu 0 sits on mobo near burning radiator and recieves air from gpu1 and 2, e949 m1500 fan80 temp71C

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1

c:\__crypto\cgminer-3.7.2\cgminer.exe --scrypt -I 19 -g 1 -w 256 --gpu-engine 1125 --gpu-memclock 1500 -o mine.address -u user.worker -p password --temp-cutoff 80 --gpu-fan 80

no config file and no concurrency set

[quote name=“Dathaeus” post=“52864” timestamp=“1389948185”]
I have 3 more 270’s and 3 7950’s on the way… eventually I am looking for a 3x270+3x7950 and hopefully get like 3.5 Mh. Might put the other two 270’s into my main rig instead, but its a Win 7 so might get like 800kh or less maybe… not sure if its worth it, but I leave that PC on like 24/7 360 days a year anyways so… might as well? I might have to do some calcs.
[/quote]

win7 is just a few Kh/s behind at those seetings, check it out, 468Kh/s on gpu0 at e1125 mem1500:

[attachment deleted by admin]

I’m using win7 right now, shall try bamt smos soon, as max i can get now is 440Kh/s per card.

I’m fiddling with two very same gigabyte r9 270 cards (and 2 more coming soon) and i’m curious about power efficiency and cooling at that impressive 960Kh/s

I’m using 600watt psu rated at 82% and it draws (measured from wall)
idle ~120watt
at 2x440Kh/s ( engine 1050, memory 1500 intensity 18) draws 430+ watts

But there’s the thing, at 949engine and 1400memory vddc can be lowered to 1.163v which gives 2x400Kh/s and power consumption of 370+watt and no overheating w/o risers.

Hi there