I cant tell you with absolute certainty what risers you have, and this is critical. My recommendation would be the measue the power line on your risers, if it’s cut run my way (USB risers should be this way). If it’s not cut, run the other way (you must).
Look up the pcie specification on the internet. Place an ohm meter on the 1x riser terminal and the other on the coresponding 16x terminal. If it’s infinite ohm’s it’s cut if it’s 0 ohm’s it’s connected to the mobo.
If you want to build a1900 watt 2PSU rigs you need test things yourself. Please don’t put your safety or the safety of you family into my or anyone else’s opinion. You need test things yourself, and own your decisions. Otherwise stick to AMD rigs that can run on a single PSU and 15 amp circuit, much safer.
the outer pins on the USB cable that connects to the riser from the 1x PCI-E slot with a multiimeter. There was 3.3V coming from the motherboard. There is also a ground connection between the riser and the motherboard.
What with this case then???
Sorry, if you have modern powered risers that is wrong. Please test yourself and confirm.
Best of luck.
Don’t measure riser pluged into the mobo under power!!! I didn’t say to plug in the riser to the mobo!!! Measure the riser unpowered by itself no mobo, with an ohm meter.
Dude ur scaring me. You need to do what you think is best.
it is from some guys tested result only
seems most riser cut the 12V power from MB, but how about 3.3V?
it seems the riser still have ground with the motherboard even 12V power cut already.
Good thanks for telling me, it’s easy to blow you mobo trying to make measurements on those tiny Pcie terminals (can short them with probe leads).
The 3.3v has to be connected as it’s the data communications voltage. All gounds should also be connected together or nothing would work. Your PSU2 does this directly on the 40 pin connector from the slave PSU.
My PSU2 is using paper clip method to power on, it did not with any link wit PSU1
if only with 3.3V connection exist…
as both PSU 12V power are isolated.
PSU1 supply power to MB and all riser.
PSU2 supply power to all GPU PCIE seems safe right?
The pcie riser has a voltage regulator on it to make 3.3v from the 12 volt rail. Newer models use a switching supply instead of a regulator.
The data that travels on the USB cable is cmos and operates on the same priciples as plugging your smart phone into your computer and downloading photos. Both with a different power supply but able to communicate without power issues.
When using a paperclip to turn on your second PSU??? Do you hit the power switches simultaneously to turn on your rig? Thats not a good idea, spend the $12 to get a 2PSU and do it right. Your 2 PSUs need to have their grounds connected idealy at a single point. With the paper clip I can’t tell you where they are connected, and can result in unexpected behavior.
This stuff is a big deal on a 1100 watt AMD rig, on a 2000 Watt Nvidia rig it’s life or death. Do it right, don’t screw arround with paper clips cuz some moron on the I ternet told you it would work.
I’m an electrical engineer of 25 years. Electricity at these wattages needs to be taken seriously.
Be safe, listen to what people have to say but verify everything yourself. It’s important.
I am using 1200W EVGA as second PSU
It come with a self test adapter, it just like paper clip method to connect green and ground
To make the PSU can power on without connect motherboard.
Yes I know the connector I have several from my EVGA PSU’s. However, it does not connect the grounds from PSU1 and PSU2 together. This is very important. A 2PSU ties the grounds together on on the 40 pin mobo connector from PSU2. Without this your grounds will be tied together somewhere else… unpredictable.
This 2nd PSU issue is so confusing…
As most people using server PSU is not possible to connect 2PSU with the PSU on PC.
Some people say the groind will be on the 3.3V riser USB
From online check result
New version riser 12V cut already
Almost all big mining farm use server PSU as 2nd PSU to supply power to GPU only.
So far I cannot find out any EE guys can do a life demo test to show difference connection issue.
I do know the risk, that’s why I keep asking people on difference forum…
Thanks for your time to reply!
Please remember that a 7 GPU GTX 1080 ti rig will draw ~1900 watts. I saw you had a post in another thread that was asking about too much current draw. This IS a problem with this rig and you cant use stock household wiring safely to power it. You need to use a dedicated line from the breaker box sized accordingly to your mains to power it safely. For a 120V mains this is a 20 amp circuit with 12 gage wiring, for a 79% load. 80% continuous load is the limit for a circuit.
Do not try to run this rig off two different circuits. If one breaker blows and its not the master (does not mater for you since you have no master) then half your rig is powered and bad things will happen.
As far as the Server PSU issue that is new to me. Please let me look into that and I will get back you you.
Server PSU’s would be the correct option for large farms… but they are not flipping two power switches to turn on two PSU’s on each rig. They have tied the PSU’s together (and the grounds), so they power up together. Just because there is not a commercial product available to do so does not mean it cant be easily made. Just as a 2PSU can also be easily made.
Sorry, but unless you can find a commercial product to link and ATX PSU to a Server PSU you you will need to build it yourself. Should be fairly easy and worth the effort.
Standard practice if for power grounds to be tied together at a hard single point as far back in the circuit as possible (at the source)… not in the load.
Hi lubu, I don’t know if this helps but this is my server psu setup: https://www.reddit.com/r/EtherMining/comments/6jjqxk/help_planning_psu_using_a_240v_psu_in_canada/
I’m buying the 2400w server kit from parallelminer. The server psu’s don’t come with a power cable so make sure you get one that is rated for 240v if your server psu runs at 240v.
Sorry to double post, but to clarify you can run your whole setup on a single server psu. Google picopsu. It lets you run your mobo off the server psu. You can get chinese version for 12$ on ebay but you’ll need a 6pin pcie to dc adapter. The one from parallelminer costs almost 50$ but comes with that adapter.
That’s what I’m using with a 6 gtx 1070 build. You need to have a step up transformer and a 240 c19 to whatever power cord. In north america we use nema 5-15p (that’s the name of the regular 3 prong plug). I ended up buying a 250v c19 to JIS 8303 power cord. JIS 8303 is the exact same plug as nema 5-15p, it just has a different name in japan and was also 10$ cheaper than the nema 5-15p labeled on. If you check my reddit post a few posts up I found that it was 10$ cheaper to get a power cord, the 2400w psu kit, and the picopsu knockoff from parallelminer instead of buying 2 evga 750w g2 psus. However, I already had a 3000w transformer so it worked out to be cheaper for me. Also use the coupon code slush for 5% off.
Where does one find a 250v rated c19 to nema 5-15p power plug
that’s the site i used. it was 8$ shipping to canada. you can google the model number if shipping ends up being too much for your location. you might get a better deal on another site.