I'm thinking of buying a Antec Sonata "Quiet" ATX case:

http://www.antec-inc.com/pro_details_enclosure.php?ProdID=15138

It comes with a 380w power supply; I'm planning on running a PIII 3Ghz, 2-3 hard drives, and one cd/dvd rw. Nothing really that crazy. Is a 380W power supply sufficient? How do I go about calculating exactly how much power I'll need?

A high end Pentium4 system with a power hungry video card and hard drives working will draw about 230W.

Your computer probably does not have a power hungry gaming card, so it'll need less. It also has more hard drives. You should definitely be fine. 380W is a lot.

*What you have to watch out for are off-brand power supplies with fudged wattage specs. Antec is a quality power supply, so you should be able to count on it actually deliver 380W.

Hard drives (7200rpm) draw 25W maximum when your computer is booting up. While running and the hard drive seeking, they draw about 10-15W. Boot up is usually the most stressful time for a power supply because of this (if you have a failing power supply, a good symptom is that your computer only boots sometimes).

Pentium4s (Canterwoods/Northwoods) draw around 80W under load. Prescotts and higher clock speed Pentiums draw more power than others. At idle your processor draws a lot less power. *I am not too sure about this figure.

Video cards vary a lot.

CD/DVD-RWs I don't know, but I guestimate it's 20W when the drive is spinning.

Motherboard and PCI cards draw up to 5W each. FW and USB peripherals also draw power.

2- You can use Motherboard Monitor to check to see if your voltages are ok.

http://mbm.livewiredev.com/download.html

Interpreting readings:
Right click the MBM system tray icon and click on settings. Click on high/low. Mouse over the alarm bells to see the tolerances of the temperatures and voltages (5%). Are any of them past their tolerances? Ignore all the zero readings. If many of the readings are zero then MBM may be too old to be supported.

I just put together a loaded computer with the Antec Sonata, and I love it. Drives shock mount on snap-in carriers (4). Mount with the connectors out and it's a breeze. Case fan keeps things cool - filtered air in - need I go on?

Loaded - 3 GHz P4, 1GB ram, dual monitor VB, 4 hard drives - two in SATA RAID 0, SB Live AB, floppy, Pioneer 107 DVD.

I've used the sonata for 2-p4 systems fully loaded with drives and dvd writer, no problems.

The case is great, I like the way the hard drives mount with air being drawn across them by the 120mm fan...

I have 400W and it's not enough. The audio volume actually frequently fades out during intensive operations while sound is playing. You can hear the fans slow down when the CPU is working hard. Freaky.

For reference, here's what I've got -

P4 3.54 GHz
1 GB ram
GeForce4 Ti4600 Video
SB Audigy2 + Front Drive
Terratec 96/24 Audio Card
DVD player
DVD-Writer
7-in-1 floppy/media drive
Coolermaster Jet4 fan
3 internal HDs (200, 200, 250)

I would guess my machine is at the mid to high end of most videophiles. So I'd say go for 500W.

I have a 450 watt, and it seems to work fine for me. My system-
CDRW- soon to be DVD burner
Canopus Storm w/breakout
Audigy w/breakout
GeForce 3 video card
3 HDD
floppy

I went for a big supply, just because I didn't want to wonder about it.

Some power supplies have their wattage rating fudged so they actually perform as well as a lower rated power supply.

If your case does not come with a good quality power supply like Antec, then you can get a good one from Sparkle, Fortron (sp?), Enermax (more expensive), etc.

Other than brand, a good sign of a quality power supply is weight. So if you're in a store then the heavier one typically is higher capacity.

Peter,

I have one computer with an almost identical layout as yours and I'm using a 380-watt supply with no problems for about a year now.

Depending on which motherboard you have or fans you are using, the fans speeding up and slowing down may be controlled by your MB on purpose. Check your manual.

If your sound is getting quieter during operation, that is not a problem with lack of power.

If you are having a power problem, your system would crash frequently or you'd get errors all the time.

"that is not a problem with lack of power."

Actually it is because it got much better when I upped to 400W from 350W, but did not go away entirely. I also have 5 case fans, and an extremely powerful CPU fan.

I have 400W and it's not enough. The audio volume actually frequently fades out during intensive operations while sound is playing. You can hear the fans slow down when the CPU is working hard. Freaky.

Is there something wrong with your motherboard? The fans should speed up when your CPU is working hard, depending on your motherboard and its settings.

2- You could try running some benchmark to stress your entire system while Motherboard Monitor is running.

http://mbm.livewiredev.com/

That program will allow you to see what your motherboard's voltages are. If they are off by more than 5% then you likely have power supply problems (although it can be caused by leaking capacitors on older motherboards).

Prime95's torture test is good at stressing your CPU and RAM and northbridge (there's a heatsink on that on your motherboard), but it does not stress your hard drive or optical drives or video card.

http://www.mersenne.org/freesoft.htm

"Is there something wrong with your motherboard? "

No, my power supply is not big enough. Actually I mis-spoke - the fans slow down when intensive operations are occuring. This is most likely the hard drives eating power away.

No. First, take those five case fans and throw them away. You don't need them. Second, if your cpu is causing your fans to slow down then you should be crashing or getting errors.

Thanks all for your replies, I think I have decided on my machine...

ABIT IS7 Intel 865PE, 800MHz FSB, Dual DDR400 $132
Pentium 4 3.2E GHz 1MB cache RETAIL BOX $399
PC3200 DDR400 512MB CAS2 (OCZ400512EL) $380
M-Audio Revolution 7.1 recording $139.9
Antec Sonata Black Mid Tower Case w/ 380W PSU $139
Western Digital 200GB S-ATA $178
Western Digital 80GB S-ATA $101


I can't decide whether or not to re-use my Matrox 450 dualhead card... How much of a speed increase can one really expect from buying one of those new $200-400 cards?

How much speed gain does a dual channel ram setup give you? Is it worth it?

Let me warn you about Abit boards- They can be rock solid... but you may have to tweak it first. Of course, I spent a year going to the Abit site, and found nothing to explain the bugs with my KG7 raid.

After one or two trips to www.sudhian.com/, I fixed them problems, and have been chugging along fine ever since. Do not take this as a warning against Abit, just that it may not be 100% out of the box.

"No. First, take those five case fans and throw them away. You don't need them. Second, if your cpu is causing your fans to slow down then you should be crashing or getting errors."

Ok, first, you don't know what you're talking about. The case fans reduce my case AND CPU temp by 10 degrees F. Secondly, it is not the CPU that is slowing things down. It is usage of the hard drive, CD drives, etc. I have a degree in computer engineering and have been building PCs for 10 years. I know what I'm talking about. If the original poster doesn't want my advice fine, but I know my own PC, thank you.

I received my electronic engineering degree in 1974 and have designed computers, at the chip level, for Pixar, SGI and those used in television and eye surgery. That gives me 30 years experience.

Running five fans for a ten degree improvement in temperature is a wasted effort.

I'll say it again, if your fans are slowing down due to a power reduction, you will crash and have errors. YOUR fans are slowing down because they are controlled by the motherboard bios.

Wrong. They're not controlled by the motherboard BIOS. They're simple fans, connected directly to the power supply, not the MB. There's only one reason they're slowing down - less power. It's the same reason the sound volume lowers. The problem was worse when I had a 350W supply. It got much better with the 400W. As soon as I go with higher, the problem will be gone.

My 3.2 is oc'd to 3.54 right now. And keep in mind everything else I have in there. Want to know my temps?

CPU - 86 F
MB - 91 F

And that's AIR cooling, not water.

Again, don't tell me I don't know my own PC.

Pentium 4 3.2E GHz 1MB cache RETAIL BOX $399
Ari, you might want to consider the 3.2C (canterwood) instead.

why Canterwood:

slightly cheaper.

less heat --> potential for lower noise. Also more comfortable if your room has heat problems.

Your PSU might last longer (no idea if getting a Canterwood will significantly improve things). At most, this is worth several dollars since PSUs don't fail often.

Uses less electricity. This can add up to considerable savings (maybe $30?). This takes some time to calculate though. If you render a lot with your computer, leave it on all the time, and are going to pay for its electricity for 4 years then you will get good savings going with the Canterwood.

Performance-wise, most tech sites like anandtech.com show that Canterwoods are ~6% faster than Prescotts of the same clock speed. However, most of them do not look at video benchmarks. One benchmark I have seen for encoding of some sort (I forget) puts the Prescott ahead by roughly 6%.

You do not have to check for motherboard compatibility.

why Prescott:
The Prescotts have the SSE3 instruction set, which offers the potential for better performance *if* programs are written to take advantage of them.

PC3200 DDR400 512MB CAS2 (OCZ400512EL) $380
Get normal RAM, enhanced latency RAM is definitely not worth it for video.

The best buy is to get 2 or 4 DIMMs of the same model RAM. Install the pair(s) in the right slots in your motherboard- usually they are color coded for each pair. Buying RAM this way ensures they will run in dual channel mode. The performance gains are really, really good compared to the small price you pay for going dual channel.

You can improve performance with normal RAM by tweaking the RAM timings/latency lower. Use memtest86 to test for stability. Also enable PAT if your board supports it. For example, the Abit IS7 does. The PAT feature is never called PAT though and will never be found on Intel boards- do your research. For rendering in Vegas, PAT and RAM timings make no measurable difference (<1%) although they might for encoding tasks.

It also may not be worth your time to tweak things since the performance gains are small. Overclocking is one tweak that does give you substantial gains, but it takes time to test for 100% stability.

2- Ari, your prices for some items look a little high if you live in the US. Check newegg.com for US prices.

3- If you want to install your OS on a SATA drive, then you should probably get a floppy since you need SATA drivers to install Windows XP.

Personally I would get PATA drives since they are cheaper and offer the same performance. As far as airflow goes, you can do origami on the cables ('cablegami') and put them at nice angles and out of the way.

I should add that the sonata cases come with the Antec true power 380 watt power supply. they rate their ps on the conservative side...

I think if you're looking at the antec ps, you'll be fine..