Bitcoin Forum

With tons of PCI-e slots?

What about a regular motherboard with tons of USB slots or tons of normal PCI slots?

What about external video card?

How do you plan to connect and power a GPU through USB? It's simply not possible.

External GPU's (or rather, cases for them) are a lot more expensive than a single motherboard.

So to answer your question - yes.

Of course.

It is the cheapest best option...

What is this bluster about GPU via USB or normal PCI? If these can be done then I doubt it will be economically viable.

Why not just buy a mobo with 6/7 pci-e slot, they are hardly special..

Such as?

once upon time a go two smart man were drinking a beer at theirs local bar  (Larry Page and Sergei Brin ) , they did have a debate about something , and they needed some answer about it . So GOOGLE was created , to find every answer there . and if you go www.goog.com and type  "7 gpu mining rig" you will have plenty of information, even some have successfully buid 8 gpu mining rig , with spliters or m.2 to pcie etc , you dont have to be that smart like them , you just have to fellow theirs build . THATS ALL  , [END OF SARCASM - in case you didnt realize]

I don't need just 7 or 6 rig mobo.

I need something cost effective, with plenty of air. Basically I need something or alt miner uses.

For example, just look at this

https://www.youtube.com/watch?v=EWVyutw3hZk

the guy don't just put all of his 7 card on the motherboard. There will be too many video card on very small spaces.

So he uses something else to connect those card to motherboard. I don't exactly know what.

He uses MSI Z97

However, that MSI 797 doesn't have pci-e connectors. It has a bunch of PCI connectors.

Currently there isn't really anything that is more cost effective other than buying GPUs at the cheapest price possible, get a cheap btc pro or other known-to-work mobo with 6+ slots and a solid PSU. Then mod the shit out of the GPUs to achieve a great watt/hash ratio. Stick all of that in/on a cheap DIY mining frame and off you go.

There are server boards with like 16 or more pci-e slots but they cost $$$$$.

Also old PCI slots have a very low bandwidth as opposed to pci-e. There are pci to pci-e adapters but I don't know what the performance of a GPU running on such an adapter would be.

Mate, are you new to mining?

These are simple pci-e 1x to 16x risers, it's what we all use to create our 6+ GPU miners. And FYI, this MSI board has only pci-e connectors (7 of them: 3x 16's and 4x 1's)

EDIT: this is what you're looking for https://www.amazon.com/6-Pack-PCI-E-Powered-Adapter-Extension/dp/B01GU94QSQ/ref=pd_lpo_147_bs_t_2?_encoding=UTF8&psc=1&refRID=TFVX63ME3HC4Z9FRYTSZ

That is exactly what I am asking.

So it has 3 * 16 and 4 * 1. All of them are called PCI-e connector. I see. Now what about the 4*1. Will that degrade the video card performance in mining?

All I need is  CPU with tons of pci-e connector then if it's not.

Also they use a USB 3.0 cable to connect 3*16 to the 4*1 one. So why can't they connect to USB slot straight?

Wether a pci-e slot is 1x or 16x has no impact on mining performance.

Careful though, it's not because a motherboard has 6-7 pci-e slots that all of them will work in a 6+ GPU rig. This is why most people buy "specialized" motherboards that are known to work without issues. The AsRock BTC Pro for instance was specifically designed for mining.

So why can't they connect to USB slot straight? Because this is not how it works :). Other than the bandwidth, a USB slot has a max power rated at 4.5W (for USB 3.0), a pci-e slot is at 75W. If you'd plug a riser into a USB port with a GPU, you'd probably fry the port and the motherboard...(some more techy people can maybe explain better).

Oh

So not all motherboard would work.

What I am thinking is that the power go from power supply straight to the GPU. All that we need next is for the GPU to transfer data, and only data, to the motherboard.

That is why I cannot understand why USB don't cut it.

I know USB don't handle much power. But power goes from power supply straight to the GPU.

Because USB is slow as hell. Also, that's not how it works.

Actually that's not the reason, in fact everyone use USB3 risers to connect GPU's to motherboard.
That means that the bandwidth is enough..

The only reason that we do this is money: The cheapest way is buy a mobo with many PCIE.
They are not special mobo, for example the MSI gaming 5 is a widely used mobo in desktop entry level pc and it's algo good for mining

usb 3 is not suitable to connect pci-e peripherals. IMHO you have two alternatives :

pci-e multiplier

1->3 like this https://www.amazon.com/PCI-Express-Port-Multiplier-Riser/dp/B0167MCHI2 (https://www.amazon.com/PCI-Express-Port-Multiplier-Riser/dp/B0167MCHI2)  (first found on amazon)
or up to 1->10 like this http://magma.com/products/pcie-expansion/expressbox-3600/ (http://magma.com/products/pcie-expansion/expressbox-3600/)

thunderblot connector
1->3 like this http://magma.com/products/thunderbolt-expansion/expressbox-3t/ (http://magma.com/products/thunderbolt-expansion/expressbox-3t/)

with thunderbolt connector you can connect and mine with multiple gpu even on laptop ....

..... unfortunally, the prices are really excessive  ::)

the more gpu's the more unstable the system. If you have many gpu's on one system and one system shuts down than you have more gpus that are not mining.
5 seems to be stable enough, 6 maybe, more I don't really see the practical use for

totally wrong ... many people have rig built with 6-7-8 cards and all working fine , perfectly stable ...
I have only 6 or 7 card rigs all of them extra stable...
yes!  you can build a unstable system with 6+ cards if you have no idea what you are doing

What are the major (top 3?) reasons multi-card rigs are unstable, in your opinion?  Under-sized PSU?  Cheap USB risers?  I think these are the reasons my build have been unstable and lock up after 4 or 5 minutes.

Dont need special motherboard, use USB pci-e adapters.

Do you mean the PCIE 1 to 3 expander?

yes we need special mining motherboard the spec are

• 1. very very cheap
• 2. very low power
• 3. huge number of pcie slot, we don't actually need x16 slots but 8x 1x slots are better
• 4. has onboard low power gpu, just for monitoring without distrupting gpu's for mining
  

to make it cheap and low power, remove integrated audio, remove extensive usb support, just need 2 USB for keyboard and mouse, remove extensive multiple sata port, just need single sata or MMC slot, we can use low power and cheap cpu such as intel atom

we are currently limited to 8x GPU per motherboard because of driver limitation and windows limitation ( on linux you can recompile the kernel to support more than 8 gpu ), if drivers support more than 8 gpu, we can use PCIe Switch chip such as Pericom P17C9X2G808PR which can split one pcie 1x to 7x pcie 1x
so with 7 slot pcie motherboard we can have up to 42 GPU's per motherboard

https://i.imgur.com/3xgPOBA.png
https://www.diodes.com/assets/Databriefs/PI7C9X2G808PR-Prod-Brief.pdf

maybe board like this
https://i.imgur.com/Wpso7Y8.jpg

this board will only need single x16 pcie slot
connected to 16x pcie switch chip Pericom PI7C9X2G404SL, each chip will consume single pcie lane, but can support up to 3 GPU per single lane, so we can have 16x3 = 48 GPU, PI7C9X2G404SL is cheap its only about 10-15$ per chip

so the spec are

• 48 slot x1 pcie through single x16 pcie lane
• 12v dc powered, you can use brick 12v power adaptor like the one is used on laptop
• onboard vga throught vga or hdmi port
• 2x mini pcie for msata-ssd and wifi card (optional)
• one 100mbps RJ45 port
• intel celeron or atom cpu built in
• 2x USB 2.0 port
• 16GB DDR3 SO-DIMM memory]
  

after mass production board should cost around 80$-100$ per board (including CPU and memory)
anyone interested to support this in kickstarter?

Unstable?...12 GPUs at 82 hours + ;)  (btw ignore the horrible eth hashrates...i just switched this rig over to eth and have been busy testing my prototype board so they still have ZEC bioses on them)

https://i.imgur.com/5724Q7p.png

I don't doubt that your rig is stable.  How does a novice like me harden my implementation? I'm asking for advice

Unfortunately what I have found out GPU mining all these years is that most of it is not even your fault, and not much you can do about it. Thats the reason I started this whole project. The cheap Chinese GPU risers you and most people are using are inherently unstable, and are a major contributing factor in why GPUs "freeze" (the other reason being too aggressive BIOS mods/clocks/voltages).