A SATA max can support 75 watt and maximum you can power a riser from it as a riser itself takes 75 watt. The VGA 8 or 6 pin cable ,usually 8 pin is to be connected direclty to the GPU, a 8 pin pcie cable can give up to 200 watt in power.
From my personal experience the IT before me working in my place had made some changes to the PSU cables and it had connected three 6 pins cables meaning 3 GPU-s to the same SATA cable and gave 450 watt in power connected to a 75 watt cable. That ended in the destroying of the PSU completely , PSU was a thermaltake 700watt. Always talk with some friend of yours which is IT or works in the IT field when asking technical advice. You can PM me, while I don't promise to answer right away, you will receive your answer within a few days.
Thank you bro. Your help is very apreciated.
Do you know a good voltmeter model?
When I connect everything I would like to observe what is consuming my rig
I probably think you are asking about watt meter in which you can measure the power you are consuming from your mining rig or computer. Kill a Watt is the most popular from the watt meters if you are living in the USA.
As for Voltmeter, every Multimeter can measure Volts , remember that there are many multimeters around and while even the cheapest Chinese model will do its job it is always better to get a premium version if you use it professionally. Everything over 100 USD is a good Multimeter while spending this amount is not really needed unless you are a pro, for your job even a Chinese clone does the job.
