i want to know how much my watts my psu is using

[markymoo]

i considering buying this watt meter
http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&criteria=meter&doy=24m11

that would give me the total watts used on my pc but this will include the psu so this wouldnt be accurate of how much watts just my parts be minus the psu. how much watts would a 700w psu use not the components but the actual psu. so which reading on psu does it say how much watts psu use then i could minus this figure from the total watts to know how much watts my parts use by my psu

or would it easier using a multimeter? if so how i use it to know total watts by psu. also can i get multimeter with temperate sensors to detect temp of motherboard etc. thanks

 

[Bios24]

Well, in theory the power supply itself doesn't "use" any wattage. If you turn a power supply on with nothing plugged in it should use nearly zero watts

But- you do lose wattage when converting voltages. (12/5/3.3v to 120/220v) This is known as the efficiency of the power supply. For example: If you have 200w in components and the PSU is 80% efficient then you'll see 240w being used at the outlet. Likewise if you have 200w in components and a PSU is only 60% efficient then you'll see 280w being used at the outlet. This wattage lose is mostly seen in the form of heat, that's why the power supply gets hot. PSU efficiency not only differs between brands/models it also depends on load. Normally a higher load will yield a bit better efficiency.

Calculating PSU effeciency usually requires a large calibrated machine to load the PSU so you can calculate the effeciency. I'm not sure how a home user would do it with the aid of just a meter and the computer.

 

[markymoo]

i will buy a 80% efficient psu such as the 750w silverstone. so i add on 20% of the total watts consumed.

 

[bobad]

i considering buying this watt meter
http://www.maplin.co.uk/Module.aspx?ModuleNo=38343&criteria=meter&doy=24m11

Never seen that one, but it should be OK. The Kill-A-Watt is presently the most popular, and costs ~US $20. They come in real handy when you're trying to reduce your electric bill, so it could save you money.

Simply multiply the reading by your PS's efficiency... usually ~.80-.85 for a pretty accurate system wattage.

Another way is to use an "Amprobe". It's a big old hoobajube that clamps on to the power cord, and reads out directly in amps. Pretty spendy though!