Am I hurting my PSU?

[Tullphan]

I've got a Corsair HX520. My rig consists of an EX58-UD4P w/i7 920 @ 3.8 GHz, 6GB ram, 3 x hdd's, 2 x DVD-R/W's, & a Radeon 4870.
The HX520 has 2 PCI-e connectors. It came with 2 PCI-e cables. I currently have a PCI-e cable with two power connectors for a card that requires such (like my 4870).
My question is, will it hurt the PSU to run a single PCI-e cable to my GPU on that single rail (18A) or should I use the two individual cables on the 2 separate rails?

 

[Blastman]

A 4870 peaked out at 165w with furmark …see …
behardware You have 18 x 12v = 216w on that rail, and they are rated conservatively. You could probably pull a few amps more than 18 on that rail without problem -- so you'll be fine.

 

[HOOfan 1]

Irrelevant. HX520 is a single rail power supply advertised as a multi-rail PSU.

http://www.hardocp.com/article/2007/12/04/corsair_vx550w_vs_hx520w/5

* Neither the included documentation nor the box makes reference to what 12v rail feeds which connectors but that point is moot as the Corsair is a single 12v rail unit.

Even if it wasn't, the different rails would only be achieved through OCP shunts and not by physically separate components, so it still wouldn't affect the PSU