.02 BTC Bounty! Help me Get my 6x R9 270 Rigs Stable

[majestictwelve1988]

Hello everybody,

BOUNTY FOR SOLUTION: .02 BTC

I'm writing because I have 5 rigs. The specs are below:

6x r9 270 GIGABYTE GV-R927OC-2GD
Celeron G1620
3 Powered Risers, 3 Unpowered
MSI Z77A-GD65
4GB RAM
32GB SSD
2x EVGA Supernova 750 Watt Power Bronze Certified Power Supply (Daisychained)
Windows 8.1

So here's my issue:

On one of the rigs, I've been able to get 6 of the cards running at about 2.858MH/S. That's about 475-477 KH/s per card on that rig.

The hardware setups for these rigs are absolutely identical in every way.

However, on the rest of the 5 rigs, the rigs crash if I use the exact same settings I'm using for the one rig... The graphics will either become completely unstable, or the rig will freeze, or a GPU in the rig will go sick/dead. I can't use the same settings I use on the one rig in the other rigs to get that nice high 475KH/s rate.

I'm worried that maybe I changed something in the software on Windows that gives me these rates on the one system but I didn't do it on all the others; can't figure out what they might be though.

The settings I'm using for the hashrate that's working on the one rig are as follows:

"api-listen" : true,
"intensity" : "19",
"vectors" : "1",
"worksize" : "256",
"kernel" : "scrypt",
"auto-fan" : true,
"temp-cutoff" : "80",
"temp-overheat" : "79",
"temp-target" : "70",
"expiry" : "30",
"gpu-dyninterval" : "7",
"log" : "5",
"queue" : "1",
"retry-pause" : "5",
"scan-time" : "30",
"scrypt" : true,
"temp-hysteresis" : "3",
"shares" : "0",
"shaders" : "1792",
"thread-concurrency" : "15508",
"gpu-thread" : "1",
"gpu-engine" : "1120",
"sharethreads" : "32",
"lookup-gap" : "2",
"gpu-powertune" : "20",
"gpu-memclock" : "1500"

Why does this work on one rig and not the others? They start out fine and then crash, while this one stays stable!

Solution must work in Windows 8.1 and give a relatively similar hashrate to qualify for bounty.

I can also do Teamviewer for diagnosis.

[darksoft]

Just clone the drive of the working rig and use it on the other rigs instead of doing a fresh install on each rig.

[Alohaboy?!]

I got some rigs with that cards too.. and I got the problem that one card was going sick and after some time the whole pc went freezing.
I was only able to solve this by lowering the hash  and I´m now running with different settings for the cards.
The setting I run is 1086 to 1450 mhz and its working totally fine @ 440khash ... so grab your card which is getting sick and try lowering the settings

[DeltaQuebec]

Also ( not sure if this is mentioned ) try only running 2 rigs per 15A circuit in you're home. 750Wx2 = 1500W should be just on the verge of what you should run. If there is any voltage sag, this can affect ALL KINDS of things. So if you havent done it yet, no more than 2 rigs per circuit breaker.

If this does it.. sweet & congrads. ( its the 1st thing I would look into & easiest )

BTC: 1DpPjsb4SiWwqUhuQaF5DD9By2LgS2BBqg

[darksoft]

He would need ONE rig per breaker at 1500 watts max... he has 2 750w psus's per rig.

[majestictwelve1988]

The electrical isn't the issue. I have dedicated 20-amp circuits for each rig. So, 2 750 watt PSUs plugged into a single surge protector plugged into a 20-amp circuit... On 5 total different circuits. The power is fine; that's not the issue at all.

Again, exactly similar hardware setup for all of them. Something is different in that one is able to push those good numbers whereas all the others fail at it.

[MisO69]

Have you checked to see if the bios versions on the cards are all identical?

[MineNerd]

You should be able to set thread concurrency a lot higher than that.

I have a 5x XFX r9 270 rig running Windows 8.1. At intensity 19 with GPU engine at 1040, memory clock at 1400, along with thread concurrency set at 21568 I get a stable 460kh/s per card.

I did not install any custom drivers. When I installed the OS, I had all 5 cards plugged in, and I let windows auto detect and install the drivers.