Power Supply Powered riser from another PSU

Jedi_James07

What's an ITX?
Original poster
May 1, 2018
1
2
Good afternoon,

I am thinking about building portable MiniPC. I like the In Win Chopin case, which has 150W PSU inside. This should be enough for 65W i7-8700, two DDR4 rams, SSD and HDD. I would also like to have GPU in it (I have spare palit gtx 1060 6gb), but it is not possible due two reasons:

1) low PSU wattage and missing PCIe 6-pin (gpu's TDP is 120W)
2) size of GPU and missing expansion slots in Chopin

First problem should be solved by using another PSU, which would need to be started using simple hack(I hope that this hack equals text *can be substituted by a power switch at this image from this guide). Fortunately I also have spare Seasonic s12ii-520W PSU. I can easily connect the PSU's PCIe 6-pin to GPU, but i think that would not be enough power, because PCIe x16 3.0 should supply up to 75W through the connector (this would need to go from 150W internal PSU). This relates to second problem below.

Second problem should be solved by using riser card. But riser cable is not able to deliver 75W mentioned above, but then I found Powered riser ribbon cable, which has also 4 pin MOLEX connector. I would connect molex from seasonic PSU to the riser card's Molex. Seasonic PSU should be able to deliver through Molex to the GPU 55-132W (based on selected PSU Molex branch), which is more than enough.

Next is how to set up riser cable management.
Someone was searching for best solution at this topic. I really like the suggested riser placement (below motherboard). But this placement has another problem: Riser cable length, because common powered risers are 19cm long with cable length only 15cm (motherboard is 17cm long). After very long searching I came to this Pci-e riser cable 16x to 16x with Molex power and length of 30cm (26cm cable). I wanted shielded riser cable, but I didn't find any with Molex power.

I have few questions about this setup:
1) May I connect molex and PCIe 6-pin from same PSU, or is there chance of blowing GPU or PSU or both?
2) Will the GPU take power from PSU's molex and 6-pin rather than from limited 150W PSU (through riser cable connected to motherboard)?
3) Do you have any other comments/notes to this set up?
 
Last edited:

mjst3rcar0

Caliper Novice
Jun 25, 2018
31
1
Good afternoon,

I am thinking about building portable MiniPC. I like the In Win Chopin case, which has 150W PSU inside. This should be enough for 65W i7-8700, two DDR4 rams, SSD and HDD. I would also like to have GPU in it (I have spare palit gtx 1060 6gb), but it is not possible due two reasons:

1) low PSU wattage and missing PCIe 6-pin (gpu's TDP is 120W)
2) size of GPU and missing expansion slots in Chopin

First problem should be solved by using another PSU, which would need to be started using simple hack(I hope that this hack equals text *can be substituted by a power switch at this image from this guide). Fortunately I also have spare Seasonic s12ii-520W PSU. I can easily connect the PSU's PCIe 6-pin to GPU, but i think that would not be enough power, because PCIe x16 3.0 should supply up to 75W through the connector (this would need to go from 150W internal PSU). This relates to second problem below.

Second problem should be solved by using riser card. But riser cable is not able to deliver 75W mentioned above, but then I found Powered riser ribbon cable, which has also 4 pin MOLEX connector. I would connect molex from seasonic PSU to the riser card's Molex. Seasonic PSU should be able to deliver through Molex to the GPU 55-132W (based on selected PSU Molex branch), which is more than enough.

Next is how to set up riser cable management.
Someone was searching for best solution at this topic. I really like the suggested riser placement (below motherboard). But this placement has another problem: Riser cable length, because common powered risers are 19cm long with cable length only 15cm (motherboard is 17cm long). After very long searching I came to this Pci-e riser cable 16x to 16x with Molex power and length of 30cm (26cm cable). I wanted shielded riser cable, but I didn't find any with Molex power.

I have few questions about this setup:
1) May I connect molex and PCIe 6-pin from same PSU, or is there chance of blowing GPU or PSU or both?
2) Will the GPU take power from PSU's molex and 6-pin rather than from limited 150W PSU (through riser cable connected to motherboard)?
3) Do you have any other comments/notes to this set up?
Just some point of view:
1) like the gdc beast adapter, the adapter take power from external PSU and i think it is the same with your riser+molex.
2) i think it doesn't matter if pcie take power from build-in PSU. It can handle it with 150W (or let say 130w)
3) follow this guy below, his cable seem awesome.