Power supply ratings don't mean much. A good 150 watt power supply can easily run a fully loaded PowerMac 9600 with a full compliment of five 7200 RPM hard drives. You'd need a bad 300 - 450 watt to do the same.
The power supply thing is very difficult to get people to understand because power supplies have been improperly rated for at least the last twenty years. A good example is my Amiga 4000 from 1993 or so. It has a 145 watt power supply. Most people would think that it's woefully underpowered and couldn't be used to run lots of hardware. On the other hand, my personal system had a CyberStorm PPC (66 MHz m68060 and 233 MHz PowerPC 604e), a 75 gig 7200 RPM IDE drive and two 10,000 RPM UW-SCSI drives, plus 144 megs of memory, a seven port serial card (with its own processor), an 8 meg PCI video card, an ethernet card, and a video capture card.
For too long power supplies were rated based on a somewhat arbitrary peak number which the power supply could output for only a very short amount of time. People got used to this and therefore assumed that if you wanted to run an honest 250 watts of power, you needed some ridiculously huge 600 or 700 watt power supply. Part of the problem is fetishism and tiny penis syndrome, of course, but in reality a good power supply can handle beyond its peak during startup, then run at 2/3 or 3/4 of its rated power continuously without concerns such as dirty power, premature failure, or anything like that. Quite to the contrary to what many people will say, a good quality power supply will work better and more efficiently when running at close to a full load.
If you don't believe me, I can give example after example of quad core servers, both AMD and Intel, with multiple hard drives and plenty of memory which are colocated with continuous use where the power supplies are typically 200 to 250 watts. Many of my servers haven't even been rebooted since last year. They're more reliable specifically because I use good power supplies, not because I use something with a number that's ridiculously higher than the amount of power my machines need.
The power supply thing is very difficult to get people to understand because power supplies have been improperly rated for at least the last twenty years. A good example is my Amiga 4000 from 1993 or so. It has a 145 watt power supply. Most people would think that it's woefully underpowered and couldn't be used to run lots of hardware. On the other hand, my personal system had a CyberStorm PPC (66 MHz m68060 and 233 MHz PowerPC 604e), a 75 gig 7200 RPM IDE drive and two 10,000 RPM UW-SCSI drives, plus 144 megs of memory, a seven port serial card (with its own processor), an 8 meg PCI video card, an ethernet card, and a video capture card.
For too long power supplies were rated based on a somewhat arbitrary peak number which the power supply could output for only a very short amount of time. People got used to this and therefore assumed that if you wanted to run an honest 250 watts of power, you needed some ridiculously huge 600 or 700 watt power supply. Part of the problem is fetishism and tiny penis syndrome, of course, but in reality a good power supply can handle beyond its peak during startup, then run at 2/3 or 3/4 of its rated power continuously without concerns such as dirty power, premature failure, or anything like that. Quite to the contrary to what many people will say, a good quality power supply will work better and more efficiently when running at close to a full load.
If you don't believe me, I can give example after example of quad core servers, both AMD and Intel, with multiple hard drives and plenty of memory which are colocated with continuous use where the power supplies are typically 200 to 250 watts. Many of my servers haven't even been rebooted since last year. They're more reliable specifically because I use good power supplies, not because I use something with a number that's ridiculously higher than the amount of power my machines need.