Is the requirement for a specific wattage of PSU more or less down to graphics card?

Question

When selecting a PSU is the primary motivation to go for a higher wattage PSU based on the specific graphics card and/or number of graphics cards (SLI, crossfire)?

In other words are all other components in a computer relatively negligible in their PSU requirements compared with a modern graphics card?

Note: I'm talking about a Mid to Enthusiast Gaming PC with a config similar to i5, 4 gigs of ram, GTX 275, WD Velociraptor drive.

Answer 1

In other words are all other components in a computer relatively negligible in their PSU requirements compared with a modern graphics card?

no, they're not negligible, you can use Newegg's online PSU calculator. you will see how each component adds to the PSU requirements.

Answer 2

The graphics card is often the biggest power user, but other components can be significant (especially the CPU).

I suggest using this power calculator: http://www.thermaltake.outervision.com/