I have a psu cable and unsure where it goes

[_jxmes]

I have a cable that the end connector is the size of my little finger and has 4 little pins on and after the 3rd pin there is a thick black plastic piece then a 4th pin. On it there is the label 'cst'. And I'm not sure where this cable goes. I have a cx 600w corsair psu, amd 6800k cpu, r9 280 gpu.

 

[C12Friedman]

Check this to ensure but I suspect that is a floppy drive cable which for some strange reason can still be found on modern PSU's even though floppy drives have long disappeared. Should be similar to the connector at the top right here http://www.playtool.com/pages/psuconnectors/connectors.html
If that is the cable, simply tuck it away

 

[Dark Lord of Tech]

I have a cable that the end connector is the size of my little finger and has 4 little pins on and after the 3rd pin there is a thick black plastic piece then a 4th pin. On it there is the label 'cst'. And I'm not sure where this cable goes. I have a cx 600w corsair psu, amd 6800k cpu, r9 280 gpu.

Connectors on the CX600:

1 x Main connector (20+4Pin)
1 x 4+4 Pin ATX 12V
1 x EPS 12V
2 x PCI-E
6 x SATA
4 x Peripheral
1 x Floppy < More than likely not needed.

 

[alexoiu]

It's floppy:
https://www.guerradigital.net/media/catalog/product/f/i/file_79_7.jpg