HX450 buzzing/hissing since upgrading graphics

[Antagram]

Since moving from a 4670 512MB (didn't require any auxiliary power) to a 4870 512MB (requires two 6-pin auxiliary power) I get constant loud buzz/hissing while in games, and intermittent faint buzz/hissing on desktop when moving mouse, scrolling down pages, and moving windows.

Not running anything overclocked. And using a HIS 4870 512MB with 10.8 Catalyst pack.

Should I worry that the PSU is likely to fail after prolonged use with this noise? Or will the annoying sound cure its self after time?

This is what is being run.
Motherboard: DFI LanParty Junior P45-T2RS with latest BIOS from 14/09/2009
CPU: Intel Core2Duo E8400 3.0 GHz
Cooler: EnzoTech Exteme-X in passive mode
Ram: 4 GB of G.Skill F2-8500CL5D-4GBPK run at PC6400 speed and 1.813 voltage
HDD: Samsung F1 320 GB
Optical: Pioneer DVR-109
Fans: 2x Noctua NF-P12 using Ultra-Low-Noise Adaptor fan adaptor
USB: Mouse, keyboard, webcam/mic built-in to monitor.

[Jay]

Are you sure its not the Graphics card? My old 8800GT does the same.

[Antagram]

You're right Jay. Which I prefer to the PSU causing the noise, as PSU will remain in system longer than graphics card.

As the previous system didn't suffer this, is it likely to be age of card? Would a higher rated PSU help (not that I have one to test with)? As this will affect the resale value.

[GoNz0]

cap whines quite common, either it will go away or you get used to it

[Jasp]

Built 3 pcs using a 4890 and all 3 whine under load, must be something to do with that line of cards, enabling vsync in games tends to help.

[Antagram]

Received a new 5850 today, and the system is still buzzing when under graphical load when playing a game.

So it looks like it's the motherboard causing it? I don't fancy upgrading system yet, but I suppose the move to current Intel or AMD range may be an option if can find a good balance between power consumption and performance.