<div dir="ltr">So, I recently built a new system. I figured out what motherboard I wanted, what cpu, how much memory and disk and then I when and used a couple of the online system wattage calculators and got somewhere between 500 to 650 watts. I could not get (find) a PSU with the right connectors for the motherboard so I ended up getting Silverstone Zeus 750 watt supply (yea, overkill). I then got a UPS from a local store. They had a sale and a higher end UPS turned out to be cheaper than a 600 watt unit, so I got a APC UPS BX1500LCD (865 watt) (again, overkill but nice). What is interesting about this UPS is that it can show the current wattage used by your system on its LED (along with other stuff). Now, my strategy for constructing the new system was to pick a motherboard that was build for high-end power and then pick cool components; I am a developer, not a game player and this system will house MythTV and Asterisk someday, well as serve as a development box. So, what I ended up with was: ASUS P5Q Deluxe Intel quad core QX9550 95 watts max for $550 (the QX9650 is 130 watts at $1000) 8GB CORSAIR (DOMINATOR) TWIN2X4096-8500C5DF Asus EN7300GT silent graphics board idle: 8.7 Watts max: 16.1 Watts 2 WD VelociRaptor Model: WD3000GLFS 300 Read/Write 6.08 Watts Idle 4.53 Watts Standby 0.42 Watts Sleep 0.42 Watts 2 WD Caviar GP Model: WD10EACS 1 TB Read/Write 7.50 Watts Idle 4.0 Watts Standby 0.97 Watts Sleep 0.97 Watts ASUS V60 cpu cooler (overkill) SAMSUNG SH-S203N DVD/CD RW Logitech SBF-90 Black 3 Buttons 1 x Wheel Logitech 967738-0403 Black 104 Normal Keys SST-ST75ZF Zeus power supply (overkill) APC UPS BX1500LCD (overkill, but very nice) Lian Li PC-A71 Black (overkill, but very, very nice) BIOS 0803 Fedora 9 64 Now, with no applications running, idle, according to the UPS the system uses 70 watts. The highest wattage I can get it to use running bunches of parallel compiles is about 125 watts. My question is: whats with the online wattage estimators? Are they all implemented by folks selling power supplies who want to sell users bigger ones than are needed? In terms of power needs, I ended up way over-specing $$ the system. Basically, I ended up with a system that uses as much power as a 120 watt light bulb. Richard </div>