What are the 'v3' and 'v4' on the red rails on Novatech's 750W PSU?

I’ve been having some issues with my GPU when watching video (computer shuts off during playback of a video - but only when I’m watching YouTube or other Flash/HTML5-related videos on any browser, doesn’t shutdown during any game I play or VLC/WMP though) and I heard that sometimes the issue can be related to the PSU not having the clock memory limits set or anything like that.

I also heard that the issue could be related to the GPU not being put into a 12v rail. I looked here: https://images.novatech.co.uk/novatech-nov-psb751_extra2.jpg and I can’t find any 12v rail, although I see the v3 and v4, what are the differences between these?

Google’d with no help. Any assistance is greatly appreciated! :slight_smile:

There are four rails on this PSU, 3.3v, 5v and 2x 12v. If you have plugged the PCI-E power cable into the RED socket then that is on a 12v rail. v3 refers to the 1st 12v rail and v4 refers to the second.

The information which you have received so far on troubleshooting this issue seems to be leading you on a wild goose chase. It should be as simple as, fit GPU to PCIe socket, connect GPU to PSU, install latest drivers, reboot.

If you are having issues from there and it’s not happening in games (which is a much higher demand on the machine than playing a video) it would suggest it’s not the PSU causing the problem.

Have you tried a different graphics card in the computer (or tried this graphics card in another computer) and seen if the problem follows the card?

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I’ve taken out the graphics card and used the onboard graphics for a few days and it had no issues at all. I know it’s an issue with the GPU for sure, just unsure whether it’s driver or hardware related. I don’t have any other computer to try the graphics card in unfortunately. Thanks a lot for answering my question about the ‘v3’ and ‘v4’ on the PSU though :slight_smile:

Think the information you were given is wrong; Took me ages to find this out; this is better answer imo. I have written this in the hope others will find it useful too in google searches…

So 12v1 12v2 12v3 12v4 reffers to you having 4 rails and so on each rail will have an A=AMP associated with each rail or some now have a group amp i.e. 80A/900w across all 4 so you can do the maths on how many cards you can fit in it.

The harder answer to find is actually V3 refers to version 3 typicaly 6PIN/8PIN GPU and is 20AMP’s Maximum and V4/version 4 8PIN is 40AMP connectivity. So if you have a high end card say like a GTX1080 or 1070 then V3 is not powerful enough when underload and you would need to be plugged in to the V4 socket. usually defined by colour Red is V3 and Blue is V4. This confused alot of people as it was never explained by power supply manufacturers; so now they just generally all are V4 sockets with a A amount spread across all rails to save confusion.

you ask why do i need to know this - it is very important to know about say if you want to put in 14 GPU’s for say a mining rig. Next thing worth knowing is effiecency in %. Easy to explain…83% means for every £1 of electricty 17p is wasted. so 91% will save you money. Many cheap power supplys wont say the effiecny avoidn like the plague…some are as low as 60%. What usually defines a good PSU is the higher the AMP on the 12v rails and the warranty it comes with. a 1000w PSU for less than £30 is impossible to be a good psu compared to a good brand 1000w which would be £100+.

Merry Xmas.