SPCR

From my research it seems that Seasonic sourced PSU's cannot be guaranteed not to whine.

I've been trying to find a quiet (fan noise), efficient PSU which I could use instead.

I'm considering the PC Power & Cooling Silencer MK III 750W as I've seen a few positive reviews, and isn't too expensive in Australia.

Does anyone have an idea if this PSU whines or is not quiet?

Would anyone recommend any other PSU which doesn't whine?

Having a PSU whine whenever you view images (Lightroom), scroll PDF documents, or do some stressful calculations is quite annoying!

It might be worth waiting for the Corsair RM series PSUs to become available in Australia. Corsair are making claims that this range of power supplies deals with the issue of electrical noise, see this blog article. Here at least the RM is priced to compete with the Seasonic G series, the 750w model being advertised by my local hardware dealer at around £100.