CPU/Mobo Fried 2 of my motherboards.... Can you figure out why ?

mavs111

Disciple
Hey everyone,

So i'm writing this post to get some help.

I've been dabbing with the idea of mining crypto and gave my hand at it for a few months with a mixed rig. I managed to learn about the issues of trying to worked mixed rigs first hand, so i decided to purchase a used Asus mining b250 board with it's CPU(an i7-7700k). When I used this board with the mixed cards i had, it worked just fine. This was powered by synchronising two psu's together. 1 1000 W psu with a 850 W psu both gold psu's.

To get done away with the hassle of mining with a mixed card rig, I decided to get 6 6600 xt's with a single 1300 W platinum PSU and started plugging them in one by one to the Pcie slots and the cpu seemed to boot up fine upto the first 4 cards and recognised the cards. When i attached the 5th card to the mobo, at first the system booted up.... but then halfway through the boot, i lost all power. When i started trouble shooting, i realised that i was getting power to the mobo while connecting the 24 pin to the mobo, but the moment i attached the cpu cable to the mobo, i did not have any power.

Presuming that i had a failed motherboard, I called upon my computer guy and got him to try and check all parts, and one by one started building the whole system on another motherboard (Msi Z390 A pro). Here, we successfully started up the cpu without attaching any gpu's. Once we reached this stage, I started connecting in sequence the 1st card that was on the b250 mobo build (the idea being that the 1st 4 cards worked, so technically that should hace worked on this mobo too).

Upon connecting the 1st gpu to the motherboard, i found my 2nd mobo fried too.

I am completely lost on what could have caused both my motherboeards from dying on me. Any inputs on troubleshooting this would be much appreciated.

Also, if anyone can recommend to me whether it is a good idea to setup a rig currently or would it be advisable to just sell all my hardware and just buy crypto?

Thanks in advance.
 
I've lost 2 motherboards due to a faulty PSU over the years.
Just one of which was in warranty.
It's behaviour was very peculiar. It would work fine until it was on some load, even though it was rated for 900w.
Although my cases were not crypto related.
Get your PSU tested
 
80+ rating hardly means anything. It doesn't convey anything about the quality of components used at all. 80+ is easy to achieve and slap a sticker on by the manufacturer.
They could actually make one gold sample and get it certified and then start selling off a whole different product under the same SKU with that 80+ gold sticker.
Get the PSUs tested I doubt both will be faulty but testing is needed to find out which one is.
 
80+ rating hardly means anything. It doesn't convey anything about the quality of components used at all. 80+ is easy to achieve and slap a sticker on by the manufacturer.
They could actually make one gold sample and get it certified and then start selling off a whole different product under the same SKU with that 80+ gold sticker.
Get the PSUs tested I doubt both will be faulty but testing is needed to find out which one is.
So i had opened a new Antec 1300 W signature for this build.

Thinking that maybe my unit was spoilt, I was given another brand new unit by the supplier but it took me the opening of the second power supply to figure out that my mobo was fried.

Would you be able to tell me the best way to have my PSU checked ?
 
Would you be able to tell me the best way to have my PSU checked ?
Well, there are certain PSU testers available which check if there are proper voltages on each rails but the caveat there is that they are not reliable to let you know if the PSU is good for running on any load.
I'm no electronic engineer so I cannot say what Ohms a certain resistor or inductor should read out or what capacitance is right for the Caps and if FETs are good.
 
I've been dabbing with the idea of mining crypto and gave my hand at it for a few months with a mixed rig.

I have some (hopefully helpful) advice about GPU mining from the few months that I mined in late 2012/early 2013. This is information that goes against the grain of what 99% of the miners currently do, but I ROI'ed 2x in four months back then with no downtime when everyone else was struggling with complications from elaborate rigs by following conventional wisdom and I see that is still the case today. As much as I don't identify with GPU mining these days, it pains me to hear about hardware failures.

The first thing is to go with multiple small rigs of 2-3 GPU's each instead of something with 4+ cards. The motherboards are cheaper, all of the hardware overall is cheaper. As a result, you'll be fine with basic 750w bronze power supplies which cost significantly less than the larger ones. And as you're limited to just a couple of cards per rig, you wouldn't need powered risers. Regular 1x to 1x risers would work just fine, so long as you shave off the end of the connector to fit the 16x connector of a graphics card.

As an example, you can get a used microatx motherboard with a built in processor like the J1800 or something from AMD's AM1 line for under 2.5k. Spare another 2k for DDR3 memory and a used SSD, bringing the total to 4.5k. A new 650W power supply is under 5k, which just leaves the negligible cost of the 1x riser cable. Power supplies and riser cables should always be purchased new. This rig can easily support 2-3 graphics cards and it costs less than 10k to start mining with them. Because these rigs are so lean and self contained, you can scale easily and not worry about having to source overpriced powered risers and exotic power supplies or dealing with complicated wiring.

The second thing is GPU orientation and airflow in regards to thermals and GPU longevity. Popular methods are either having them mounted side by side with fans blowing across them in a metal frame, or hanging from a wirerack with zip ties also side by side. This is absolutely nonsensical. It's best to have the GPU's fans all face the same way, the front of your wirerack setup. They'll all have clear access to fresh air equally, and position the rack near a window with an always-on bathroom exhaust fan. With this setup you'll never have to worry about stagnant or recirculated hot air ruining your thermals.

Smaller rigs, unobstructed front-to-back air flow.
 
I never looked at it in that format.... 2/3 cards per mobo.

Primalrily due to space shortage for me while im trying to mine out of my bedroom to be honest.

What i did do though i i bought an open air rig so that i can build upto a 6 cards rig all aligned in one direction which would be supported by pwm fans on the case for cooling. I avoid keeping my windows open given i live by the sea. There is a lot of moisture laden salt air by virtue of this ... and tends to rust metal up more than not.

I intend to test each new card individually for now (Unless it is suggested otherwise).
As a safety measure.... for now i have bought new risers for all the cards .... and hopefully my RMA'd motherboard doesn't fry out.
 
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