Looking for a PSU formula

[Locut0s]

I've been thinking of building a new system recently and it hit me that I really have no idea how to calculate what minimum PSU I should get for any given configuration. I did a quick search and ran across the following calculator on the net that is quite helpful.

http://www.jscustompcs.com/power_supply/

However what I'd really like to know is how to calculate this kind of thing myself. Is the best way really just to search the various vendor web sites looking for power ratings then just add them up and add say 20% or so, or is there actually a formula you can use?

Thanks🙂

 

[Sonic587]

Why not list the components of the system here?

 

[mechBgon]

Originally posted by: Sonic587
Why not list the components of the system here?

^ yeah. 🙂 It partly comes down to personal philosophy too. Do you want "just enough," or do you want to buy a PSU that doesn't need to strain itself? I built a system for one of my sisters that's running an AthlonXP 2500+ at stock speed, one memory module, one hard drive, one optical, and a leftover GeForce2 GTS-V. It's running on an Antec TruePower430. Definitely overkill, but I'll bet you it lasts and lasts and lasts. She'll probably keep it at least five years.

 

[Henny]

Here's a much better link:

http://takaman.jp/D/index.html?english

You need to look at each voltage rail's output vs. the overall watt rating.

I've seen 350 watt power supplies that could supply 18a from the 12v rail yet other 450 watt power supplies fall short. It's also not wise to buy low end power supplies even if they provide the amperage you need. You get what you pay for.

 

[Locut0s]

Thanks for the reply, and the link from Henny.

Here is a fairly good list of what will be in the new computer some of it is in my current computer. A few things to note I don't want the bare minimum but neither do I need a huge amount of overhead, I won't be over clocking this system.

Athlon 64 3800+
Athlon 939 Mobo possibly either the (Abit AV8 Deluxe) or the (MSI K8N Neo2 Platinum)
1 Gig of ram (2 512 sticks). Probably generic ram by maybe name brand.
One WD 100GB drive + Two WD 120GB drives (both 7200rpm EIDE)
GeForce 6800 GT/Ultra OR ATI Radeon x800 xt
Sound Blaster Audigy Platinum
Dual Layer 16x DVD+/-R(W) drive
USB Mouse/USB Keyboard/USB Printer/USB Scanner (None of these should draw much if any power except maybe the mouse since it is a Logitec MX900 wireless one)

It would be nice to have some headroom, to say add some more ram another HD and one more PCI card but as I said I'm not going to be over clocking or anything. Oh and this computer is on 24/7 just about.

 

[Sonic587]

What is your budget?

 

[Locut0s]

Sonic587 What is your budget?

I don't have an exact budget at the momment so I'll just have to say I'm aiming for a mid to high end system that's on the high end. Basically I just want a powersupply that can handle the job with some overhead to add some more components in the future, it doesn't even have to be a really well known brand name since I am not overclocking and don't expect to keep the system going for 10 years or anything.

 

[stevennoland]

Originally posted by: Locut0s

Sonic587 What is your budget?

I don't have an exact budget at the momment so I'll just have to say I'm aiming for a mid to high end system that's on the high end. Basically I just want a powersupply that can handle the job with some overhead to add some more components in the future, it doesn't even have to be a really well known brand name since I am not overclocking and don't expect to keep the system going for 10 years or anything.

So do you want a dragster or a daily driver? Why shouldn't a good power supply last 10 years? I'll tell you why. People still plug their computers into a cheapo power strip. If you want to protect your multi grand systems, why shortchange them with filthy power? I have two systems plugged into a Monster Power 'Power Bar' 1100. This line conditioner has stage 2 protection. Go to monsters site and read on it. I spent over $2500 for my voltage stabalizer and line conditioner for my home theater. Should my computers deserve any less?

 

[mechBgon]

Originally posted by: stevennoland

Originally posted by: Locut0s

Sonic587 What is your budget?

I don't have an exact budget at the momment so I'll just have to say I'm aiming for a mid to high end system that's on the high end. Basically I just want a powersupply that can handle the job with some overhead to add some more components in the future, it doesn't even have to be a really well known brand name since I am not overclocking and don't expect to keep the system going for 10 years or anything.

So do you want a dragster or a daily driver? Why shouldn't a good power supply last 10 years? I'll tell you why. People still plug their computers into a cheapo power strip. If you want to protect your multi grand systems, why shortchange them with filthy power? I have two systems plugged into a Monster Power 'Power Bar' 1100. This line conditioner has stage 2 protection. Go to monsters site and read on it. I spent over $2500 for my voltage stabalizer and line conditioner for my home theater. Should my computers deserve any less?

Wow, $2500 just for the voltage stabilizer & line conditioner? :shocked: Zoiks! You must have a better-paying job than I do... mech's world

Anyway, I'm used to people freaking out at me for recommending an "overkill" power supply but let's look at the big picture here. The difference between a mainstream Antec SL350 and an Antec TruePower550 is still only about $50-$60 last I checked. Compared to the range of prices in CPUs or video cards...? Yeah. Not a large cost to move up a little and get a TruePower 480 or something. It's worth noting that the Abit AV8 has some reported problems with TruePower power supplies, so maybe consider an Enermax or PC Power & Cooling unit there.

 

[imported_whatever]

i would buy a fortron 400 for about $65 or step up a bit to a fortron 530 for about $75 - both very good deals. fortron makes great psus, as well as being priced quite well. for the price, they cannot be beat, and even not counting the price, they compete damn well with antec and enermax psus.

 

[Locut0s]

Thanks for the replies.

stevennoland: I'm not going to be spending bucket loads of cash on the PSU. Yes I know it's an important piece of hardware but like I said I don't plan on keeping the computer for 10 years or anything. If I was building a top of the line home theater system like you suggest then I might consider that kind of thing since hardware there has lasting quality. That's why I spent more money on my monitor last hardware upgrade (21" Sony) since I'm hopping it will last me longer. But with computers getting obsolete in a little over 2 years I don't care for anything in the case to last more than 2 or 3 years.

mechBgon,whatever: Yeah looks like I'll be getting a powersupply in the 450-500W range. Thanks for the suggestions.