Topic: Motherboard designed for mining, and better riser cables in this thread. - page 4. (Read 63329 times)

What I read.

If you use the Molex connectors on the board, DONT use powered risers, they will fry your gpu.

Simple rule of supply/demand, they won't go more than $1 if the GPU mining is completely dead.

Maybe? But why would you risk frying your expensive hardware over 50 bucks in risers (at most)?

Would it be ok to go with non powered risers with 3 cards only on H81 BTC Pro with molex connectors on the board ?

Part of the cost is in the extra hardware, like the USB 3.0 sockets, the cable itself, and the bigger pcb itself. Also, the USB 3.0 cables have to generate 3.3V for pci-e on the "riser" card itself, so there's a bit of added circuitry.

In November I was getting USB 3.0 risers for $6.60 in quantities of 14 pcs. Blame the Chinese gouging and scryptcoins gaining ground for $20-30 riser cables.   

I am also wondering where the cost for these comes from if the cable is easier to get. I know ribbon cables must be cheap too but $20 for a riser seems ridiculous to me. I am used to getting $8 25cm powered ones on ebay

I plan on using the same board with the same PSU but only 1. For start I'm gonna plug only one card into the x16 slot and afterwards I'll add some more. Hope I wont get into some kind of issues.

The only thing that troubles me are those risers, which one should I use in this particular scenario. Seems like there is no "correct" opinion on that matter. Powered ones or the simple ones but with molexes connected to the Motherboard.

Just to repeat I dont plan on putting more than 3-4 cards on that H81 Btc PRO... My guess is that 3 cards(with one card put directly into the x16 slot without a riser) with standard risers should work properly with powered molexes on the board 

At least you openly admit it...

No, it does not work that way. The riser cables use USB 3.0 cables because they are cheap, already manufactured, and they serve the purpose well. Please do not try plugging one into an active USB port.

I'll be the retard here and ask... so we can't plug the usb3 into a usb port instead of the pci1x can we? That would be way too awesome...

Hey people! I'm back with some news about the ASrock H81 Pro BTC.
I setup the first 5 GPU rig last night and configured it this way:

- 2x Corsair HX850 PSUs (connected together with splitter cable)
- 30cm 1x-16x "inferior" powered ribbon risers
- PSU#1: mobo, cpu, all five risers powered and two 280x cards
- PSU#2: three 280x cards and hard drive
- all risers going to five 1x slots (left the 16x slot empty)
- BOTH molex connectors on motherboard are left unplugged because I figure the risers are already powered nicely!

Turned it on, loaded windows 8.1, drivers, copied cgminer and all settings from another rig and it's hashing at ~67C (standup fan blowing onto the rig as well) without ANY issues at around 3.6Mh/s!
No need for sensor pins, no driver issues or windows not seeing any cards, no dummy plugs. This motherboard is a dream to setup 5-6 cards on compared to any others I've used in the past.

Hope this helps someone.

Cheers,
llama

With 16x risers you don't have to short the presence pins. This is a huge PITA to get right. Once you learn to do it, it becomes pretty easy. Getting the correct width/length of tiny wire in the very small certain hole on the PCI-E lane is difficult at first. That's the main reason I have some 16x risers, as it was my first rig and I wasn't good at shorting the presence pins yet. They don't obstruct my airflow at all though. Who points their fan sideways at their GPUs? That doesn't make sense. It should be facing straight on with little to no blockage caused by the risers. I've broken one of each already (1x and 16x) already from fiddling with it too much. It's all cheap crap from China if its the ribbon risers. Don't care what bus speed it is. I don't think it creates any extra noise. I have 3x 16x risers on my first rig with 5x GPUs and it works just fine. The only bad thing is they are hard to maneuver like you said, but most open rig setups have the card right above the PCI-E bus so its not too big of deal as long as they are long enough.

I don't believe they will cause as many issues for people as you are making out in this thread. Most people use ribbon risers just fine and have no issues, no "smoke" as you put it. I also think you should still use the molex connector on the board as well as powered risers. The more power you can provide your GPUs the better, especially with 5+ GPUs. Why not? Who runs out of molex connections with a high wattage PSU? There is no harm in it, only possible advantage.

I am not contesting your opinion of USB risers though. They are definitely the best option at this point. If they were out when I'd setup my rigs for decent price, I'd of used them. But once you get a rig going there is no point to upgrade stuff like risers... If it's working, just leave it be.

RE: Asrock H81 Pro BTC. I wouldnt use that mobo. It's a piece of junk. What's the point of the PS/2 and parallel ports? Sounds like ASRock had some spare parts leftover from back in the day and figured this would be a good way to use them up.

Thanks for the tip! I'll take a look.

This is the supplier I deal with and he's been nothing but wonderful. All the cables that I've gotten from him have worked flawlessly to date.

https://www.hashratestore.com/shop/cables/powered-pci-e-1x-16x-riser-cable-with-molex-extra-length-30cm/

I'll try and report back next week!

Good luck with the ribbon riser cables, especially the extra long ones.

Before you start using them, I would check that the 12V line is not shorted to the ground. The way they add supplemental power to those ribbon risers is not very clean, and if they miss by one (or two?) pin pitches you've got a dead short to ground that will certainly make smoke.

Thanks for the suggestions.

I too have a few rigs running six 7950's successfully using good quality powered risers. I agree that you CAN do it, it just takes a little patience

As for this ASRock mobo, I will do like you suggest and what my gut feeling tells me to do: run all risers powered, but omit the molex connectors on the motherboard. I figure it should work the same as any other motherboard I've used in the past. I also wish I could use USB risers, but they are crazy expensive and when I've got 10 rigs to build next week, it can get pricey. I also just got a shipment of ~70 brand new and quality risers (30cm!) yesterday so I've got that ready to go.

1) People find new and creative ways to burn things up all the time. I can't tell you what they did, because most of them don't even know for sure. There are hundreds of threads and questions asking how to get 6 gpu rigs running, but I apparently have the only ones in existence? You don't often hear about things that go well, you hear about the screwups and mistakes.

2) Using usb riser cables, don't plug in the molex connections on the motherboard. Run the riser cards and GPUs however you want, so long as your power supplies are evenly loaded. If you use ribbon riser cables expect whatever comes your way with those cheap pieces.

So we're back at square one then.

1) why are people having stuff shorting and frying with various combinations of PSUs, risers and motherboards
2) what is the best configuration running this ASrock motherboard? Connect ALL risers, molex on mobo and power to video cards to any cables on any number of power supplies? No risk?

I sure am, thanks for noticing!

The system can not "pull power back." Electricity follows the path of least resistance. If the traces/wires to the motherboard are still intact power will flow from both the motherboard and riser cables extrenal 12V INTO the card till the resistance of the motherboard traces shifts the load to the riser cable's supplemental 12V line nearly exclusively.

Besides, this just further proves my point. If the risers are already electrically isolated, it MATTERS NOT what power supply is feeding the riser cables.

I find it funny the very second post in the link you provided confirms what I pretty much just said though.

Are you 5 years old that you need to resort to insults like that?

The system can pull the power back through slot and through the motherboard traces again. Which is why people actually CUT the +12V wires if the risers are powered. So when you're running two PSU's, the one that's not connected to the motherboard may pull some power back through the slot down the riser.

Here's the example: http://forum.feathercoin.com/index.php/topic,2193.0.html

They don't even have to be on the same power supply, that's just dumb. Some gpus would get power from one power supply via the risers, then the rest via the 2nd power supply. So, if it's OK for a GPU, why would it make a difference for the motherboard???

I give up, can't believe people so "knowledgeable" can be so dense....

Alright so after chatting with a few knowledgable people on IRC, I came to a conclusion:

If you power ALL risers with the SAME PSU that powers the motherboard, then there is NO need to use the molex connectors on the ASRock motherboard. Same applies when you have two PSUs per rig!