Thanks man, but I guess an usb adapter is not able to freeze a machine like this. What's more I had them working fine on 2 Intel / Asus systems (Desktop and Laptop)

It is the entire machine. I need to power cycle it to come back (with Always On after power failure on the BIOS). However, now that you mention it, I'm not sure if it locks up without being mining. When I come back I will leave it 24h powered on without doing anything. That can help in troubleshooting, but obviously defeats the purpose.

To make matters worse, the store where I purchased the components have a strict policy. They are *this* close to lose my further investment.

I'm not using ethernet, but 2 wifi usb adapters. One is a generic dongle with Ralink 2870 chipset. The other is an Alfa AWUS036H

I already did that too.

Thanks, I had tried it already. I also tried one core per unit, i.e. triple. They are also downclocked to 800 Mhz. With dual I managed 2 hours of continuous operation and then a lockup.

Can you suggest me the cheapest (even used) CPU that works with these motherboards?

That said, one should not be forced to tweak for stability the default bios settings or any setting. Slow or lacking features, sure, but not unstable.

Be certain that I keep my word and give away the 0.1 BTC if a solution is found. That's nothing compared with how wasteful this have been and the peace of mind I lost

Edit: Another lockup just happened... 

So, I have a Gigabyte 990FXA-UD3, an AMD FX-6100 CPU, a XFX 850W PSU and 1x4 GB Kingston Value Ram with currently mining with a 7970, a 6950 and a 7870

I can't get around random lockups and freezes.

At least this was attempted:

- I switched the PSU by a Corsair 650 (using just 1 card), the RAM by 2x2GB Gskill Ripjaws and the motherboard from an Asrock 970 Extreme4.
- I've disabled every single feature on the motherboard not useful for mining: Sata, firewire, sound, power saving states, turbo core and others. Likewise on Windows.
- Underclocked to down to half the speed and/or overvolted by 5 to 10% every component on the bios. I relaxed timings on RAM and ran passes of memtest86 without errors.
- I ended up modding the BIOS of the 3 videocards, however the rig locks up even if the GPU cores are down at 500 Mhz.
- I removed the hard-drive and I'm booting from an USB pen. I tested Win7 32 or 64 bits. I used one GPU at a time and switched slots.
- I've read threads online of people complaining about lockups and freezes on this platform.
- It gives me the impression that the rig locks up when left on it's own. I don't remember it even locking up once while interacting with it.
- I updated the bios of the motherboards and even used a suggested bios by someone from Asrock.
- With the autoruns.exe utility, I disabled un-needed device drivers. I test with and without MB drivers installed.
- I've read plenty of threads. For example http://forums.tweaktown.com/asrock/50970-asrock-970-extreme4-fx-8350-unstable-stock-settings-8.html and even http://www.overclock.net/t/1140459/bulldozer-overclocking-guide-performance-scaling-charts-max-ocs-ln2-results-coming
- Temperatures are fine and ventilation is good. GPUs below 60ºC and everything else below 40ºC, even down to 10. I've checked all temperature sensors available via software. Fans are working fine. The CPU cooler has Artic MX-4 thermal paste applied.

I'm pretty sure that experimented more stuff than this. The point is that I need to do something substantially different to fix this crap.
Could someone advise on how to solve this? Thanks.


Edit: I will leave for a few days to be with my family. Please keep replying to this thread, even if I cannot post from there.

Edit2: I can send 0.1 BTC to an escrow if you like. However the machine has to be stable mining 24/7 for at least a week

I suspect that cow abduction in the U.S. have to do with post-nuclear test mitigation. The military steal and dissect the cows to test the presence and measure radioactive elements that accumulate in the internal organs

Seriously, who gives half a shit about middlecoin's lack of transparency or crappy website or lack of stats and coins being mined? The only thing that REALLY matters is which pool pays out more!

I bet that while people were burdening hashcows devs/operators with yet more worthless nonsense and nitpicking, the middlecoin guy was silently adding and milking Dogecoin giving those stratospheric payouts. So, being opaque and shutting up about which coin is being mined, ends up being better after all!

"UFO's" have NOTHING to do with aliens! Flying saucers and other advanced spacecraft are probably made by Boeing and Lockheed Martin.

If you want to seriously discuss any this, the very FIRST step is dissociating "aliens" from "flying saucers" inside your mind. Make the effort! That bogus association has to do with repetitive and extensive propaganda and obfuscation in the U.S. media and Hollywood since the 50's. So, at the end of WW2 they were made by German scientists, a few years later they were made by ... aliens?

 It's unbelievable how people still fall for this crap after being aware of nukes, HAARP, petrodollar, NSA scandals, hidden or stalled scientific knowledge and other critical topics

The offer is still good, but I'm done with advertising and perhaps posting for a while.

In advance, Merry Christmas and Happy New Year everyone! 

The PC bios has "spread spectrum" options to mitigate this kind of attacks

Surely any coin "devs" pump their own stuff, but the "dump" part it's because miners are dumping it at whatever price...

Increase the intensity on the 1st card, 1 step at a time while it doesn't give HW errors.

If it does, use a lower thread-concurrency and try again.
If there are still problems, use now a higher thread-concurrency and -g 1

I believe I didn't over simplify anything, I went to the point.

Let's even be more direct:

Cost of ~3 Mh/s:
GPUs 4 280x at $1200  
PSU: $150
MB + CPU: $150
RAM: $40
Extras (3 risers, 1 usb pen or HD) : $60
Total: $1600
Resale value after mining: 50% = $800

Your cost: $3000
Resale value: 0 ?

Of course it takes time and effort to setup and research GPU rigs. It however takes stomach to fork $1000 per Mh/s.

This isn't Bitcoin ASIC all over again. When promoting and saying that Bitcoin ASICs save power and you'll mine for longer, it was a given that they offered 100x + the speed of a GPU. They offered 2 orders of magnitude better on both power efficiency and speed. Scrypt asics provide the same speed at much higher upfront cost. For some reason that 100x vs 1x is only a minor detail in this discussion!

Bump!

I really need this kind of watchdog devices. I'm using a timer that whatever happens, cuts the power and forces a restart cycle every 4 hours. Far from efficient and these redundant start-stop cycles are stressful to the components

How can I connect from one PC to the reset pins of the other?

If cryptos continue to gain popularity, electricity cost will be residual. If what you get from mining is eaten by 0.1 - $0.25 kW/h, then crypto is not popular

Not to litter this thread and the nice guide, but please ditch that "sudo" and "Being logged in as the root user is not recommended for various reasons, so you want to create a non-privileged user."

Damn I hate the Ubuntu "community" 

Scrypt is indeed ASIC resistant if the vendors can only offer "power savings" in exchange of the absurd upfront cost



Edit:


LOL!

Could you guys provide EVIDENCE of what you are claiming?

Where's the original thread?