PSU's either works or it doesn't, right?

[Antoneo]

My question is, are power supply units straightforward in the way they work meaning it either handles the given load or it doesn't, there is no gray area called chance.

The reason I ask is because I have an Antec TruePower330 and I'm not sure if it can provide enough power. Here's my setup right now:

P4 1.6@2.1 GHz
512 PC2700 DDR RAM
EPOX 4g4a+
ATI R8500 LE 64MB

1 80GB Seagate Cuda IV
3 200GB Seagate Cuda V
1 32x LITEON CDRW

1 Turtle Beach soundcard
1 Firewire card
1 Floppy

It runs Prime95 stable for several hours and the voltage drops to about +11.39 lowest on the +12V rail and it doesn't fluctuate much in the 20 second readout to file.

Now, if I add another 200Gb Seagate to this system, will I immediately know whether or not the power supply is providing enough amperage on the +12V rail? Will the computer just refuse to start or will I have to worry about an unstable system? I know that the hard drives require the most power on startup to spin the heads. I'm worried about data corruption across my hard drives as a result of not enough juice... is that an unfounded fear?

 

[Markfw]

your fine.....But the thing you would notice is it may become unstable if it wasn;t good enough.

 

[Navid]

There is a gray area!
The average DC output voltage of your PSU is a function of how much current you draw from it. The more you draw current (more and power-hungry components), the lower the voltage goes. The components that use this voltage don't stop working right below a voltage. At what voltage a component fails is a function of its load, its temperature its age, ...... This may result in occasional crashes.

A more problematic-to-see cause of failure is the instantaneous voltage of the PSU. You can measure the average voltage by using a digital volt meter and confirm that your PSU is OK under load. However, you cannot see the instantaneous voltage. For that, you need an oscilloscope. Just because the average voltage is OK, does not mean that the voltage never drops too low.

Anyway, it is a good idea to find out why your 12V rail drops to 11.39V (5%).
It will very likely drop even more if you increase the load on it.

You should be OK if you can run memtest overnight with no errors and prime 95 overnight and still running the next day. If you increase the load, you can run these tests again and see if you are still OK or not.

 

[Matthias99]

Anyway, it is a good idea to find out why your 12V rail drops to 11.39V (5%).
It will very likely drop even more if you increase the load on it.

Solid advice, but keep in mind that if you're getting these readings from something like MBM5, they could be wildly inaccurate. Use a digital multimeter for more accurate results (I'd trust even a cheap $10 meter to +-0.01V). I don't think you should have any problem with that system and power supply, though. Drives just don't pull that much power.

 

[Zepper]

Yeah, the health monitor chips/software aren't necessarily all that accurate - use a DMM for a crosscheck as Matt said. Unf. PSUs do have gray areas...
.bh.

 

[Antoneo]

Hey guys, nice to see responses. My other threads usually don't fare as well

Originally posted by: Matthias99

Anyway, it is a good idea to find out why your 12V rail drops to 11.39V (5%).
It will very likely drop even more if you increase the load on it.

Solid advice, but keep in mind that if you're getting these readings from something like MBM5, they could be wildly inaccurate. Use a digital multimeter for more accurate results (I'd trust even a cheap $10 meter to +-0.01V). I don't think you should have any problem with that system and power supply, though. Drives just don't pull that much power.

I'm don't know too much about power supplies, how would I figure out what is making my voltage drop 5%? I thought that was pretty much the safe threshold. I am getting my results from MBM but didn't know that they could be wrong. I've a digital multimeter from RatShack but have never tried it on a power supply. I suppose a search here or google will show me how to do it.

The strange thing is, there are so many (pretty much daily) PSU threads with people worrying if their PSU will make it but when I check the specifications they are worried about, it is for a very basic setup. The only component I can see that would take a lot of +12V is are the CPU and from what I understood the hard drives. Today's CPUs draw a lot more on the +12V rail I guess, especially overclocked? These guys are buying 480 Watt PSU with 20+ amps on the +12V... sounds like overkill to me.

 

[Markfw]

Keep the case open, and use a 4 pin molex. The 12v is yellow, and the ground is black, and the red is 5v. Stick the vom in the holes of a spare connector.

 

[Antoneo]

Originally posted by: Markfw900
Keep the case open, and use a 4 pin molex. The 12v is yellow, and the ground is black, and the red is 5v. Stick the vom in the holes of a spare connector.

Thanks .

 

[ShaqDiesel]

I will say that I just had a PSU go bad, and my PC would shut down randomly for a few weeks, thought it was drivers, but then the whole thing died, ended up being the PSU slowly dying.l

 

[Antoneo]

Well, I just installed another Seagate 200GB and I'm happy to say that there's no problems. Like I said, it's just wierd how people go bonkers and buy 500 Watt Neopower Antec PSU for very basic setups.

 

[Boonesmi]

Originally posted by: Antoneo
Well, I just installed another Seagate 200GB and I'm happy to say that there's no problems. Like I said, it's just wierd how people go bonkers and buy 500 Watt Neopower Antec PSU for very basic setups.

a high quaility 300w powersupply is more then enough for the huge majority of systems

i mean if your running a dual opteron with 5 scsi drives in a raid then might just need a little more power

but to be fair my enermax 360w powersupply had no problem running my dual opteron system for a couple weeks while waiting for my new 460w enermax (granted i dont have 5 scsi drives, lol)

 

[Goi]

Another "gray area" comes from the fact that the various components of your system aren't drawing the same current all the time. For example, when you run 3DMark05, your graphics card/CPU is obviously going to be drawing more current than if you were running Photoshop. Or, when you're defragging, your HDD is obviously going to be drawing more current than if you were running Office. Stuff like that.