This is needed
Not for most PSU. The quick and easy check is to look at the PCIe power cable. Does it have two connectors one one "string"? If so then using a splitter doesn't really do anything
*
PSU ------------------- PCIE connector 1 <----- use only this connector
|
---- PCIE connector 2 <----- don't use this connector, use another wire for a 2nd connection (wrap me with electrical tape)
The connector can handle more current than is needed so it is just a question of "can the PSU push enough current to the connector".
You could use a splitter to connect the connector 1 & 2 in diagram above but the same amount of current is flowing through the cable regardless. If a board pulls 20A then at the point marked * it will have 20A of current regardless of if you are using a splitter or not.
So for four connections it would be something like this
|---|
| |------------------- PCIE connector 1a <----- Connection #1
| | |
| | ---- PCIE connector 1b <----- Don't use me
| |
| |------------------- PCIE connector 2a <----- Connection #2
| | |
| | ---- PCIE connector 2b <----- Don't use me
| P |
| S |------------------- PCIE connector 3a <----- Connection #3
| U | |
| | ---- PCIE connector 3b <----- Don't use me
| |
| |------------------- PCIE connector 4a <----- Connection #4
| | |
| | ---- PCIE connector 4b <----- Don't use me
|---|
Each set of wires is carrying no more than 1/4th of the total load. So 1000W / 4 = 250W / 12V = 20.83A / 3 conductors = 6.94A per conductor which is below the limit for both the wire and the connector.
