Afternoon all, Anyone who follows my developer journal might be aware that I had some PSU problems when I upgraded to a GeForce 8800 a while back. Seems that 420w of generic PSU wasn't quite enough grunt to stop the 8800 toppling over and I got an unpleasant reminder of how unstable PC's can be at times [grin] If a USB device is proving to be very unreliable, to the extent that Windows will keep thinkings it's been removed and plugged-in again as well as other odd availability issues (and it occasionally claims I have a USB 2 device plugged into a USB 1 port, even though it is *definitely* a USB 2 device in a USB 2 port) could it be down to the supply of power? FWIW it's a wireless network adapter running entirely off the PC with no additional power source. I also know that I'm probably killing the PSU already - 4 HDD's, 2 optical drives, a GeForce 6800 and an older less-efficient CPU all running off a 370w (iirc) power supply. I'm basically thinking that adding this new device to the mix is tipping it over the edge and the PSU just can't provide the juice to the USB device which is in turn confusing the OS as it keeps powering down... Would that theory make sense? I don't know much about the USB specification so not sure how they're supposed to respond to low-power situations. I'm well aware this isn't a tech-support forum, so I'm as much interested in the general topic - this as well as the aforementioned 8800 incident have got me thinking [smile] Are there any easy/reliable ways of measuring the load on a PSU? Most components these days claim to go into a low power mode (which is the only way I can justify my 370w PSU powering around 400w of equipment [oh]) but the real-world details for this are impossible to find it seems... Another thing I've been considering is just the price of running systems with ever increasing PSU ratings - a recent bill I received states I get charged 8.8 pence per kilowatt hour. Not exactly much, but if I were to run all my kit at full-tilt 24/7 that's a good £75 (~$150) a month I'd be burning [oh]. Realisticly it's more like £5/month just for my PC's but still, £60 a year just to have the things turned on is worth knowing about... Whilst I'm not the most concerned individual I do try to keep a bit of a check on how much energy I waste these days (what with the whole global warming as well as an aging power grid [rolleyes]) and working through the numbers doesn't put me in such a favourable light [lol]. I'd best stop rambling now... just curious as to anyone's thoughts on the above points/questions. Cheers, Jack

I won't answer the technical question. I believe that your PSU load is not that relevant - since the PSU contains a transformer, it will always suck the same amount of current, unless I'm mistaken (because there is two separate circuits). So you'd better watch the global load of your computer (which should be N W/h, with N = PSU power).

I did a post on a similar subject on my blog (well, not that similar; but I am concerned about how I, as a software developer and software architect, can fight against global warming when doing my job). My conclusion is that we should make software that don't need much resource - so that we don't need a huge computer to run them. The exact contrary of Windows Vista, for example. The result should then be:
1) decrease of the average power consumption of PCs
2) resource economy, which should create a more sustainable business.
The resource economy thing is important: by wasting energy, we are wasting natural resource. We also waste a lot of other natural resources that don't bring us energy but that are used to create our machines (petrol used to create the plastics of my case, metals, and so on). What will happen when the price of petrol/metal will be too high? Are you prepared to pay 300$ for a case?

We, as computer freaks, don't put much of our attention to this issue. When I'm in Aix en Provence, my computer is online 24/7 (I have a 300W PSU IIRC) - even if that doesn't count much on my bill, it's still a big hit - as I only use it the evening when I'm at home (that's 3 to 5 hours per day; nearly 90% of wasted power - no wonder why my main room is always hoter than my bedroom in winter).

When we buy a more powerfull rig, we have to update the PSU. I've seen PSUs of 850W. Having the PC running 24/7 with such a PSU would probably not hurt my bill that much, but hell, that's a good slap in the face of global warming. I guess we have to take care of this.

I'm not sure I'm clear...

Hi JJ,

I am not a hardware guy myself, but I have recently been checking out several hardware forums because I am going to do a full system upgrade in a few months.

All the following comments are based this research, rather than first hand experience of the latest hardware, although I have had failure of cheap PSU's in the past.

If I was going to buy the components today, the GFX card I would go for would be a 8800gts 640mb ( to fit my budget ).

Regarding the PSU in particular; seeing as I am doing a full build ( which I can't afford to do too often ), I am going to go for a quality PSU @ 600w - 620w for some future proofing (considering the Seasonic M12 600w Modular ATM).

Some points I have gleaned from the hardware forums I have visited, which seem to have a general concensus:

1) Don't skimp on the PSU when using other high end components, especially those with relatively high power consumption, as this has a higher risk of component failure or malfunction.

2) Quality PSU's differ drastically from generic PSU's ( at the same watt rating) regarding voltage stability, maximum amperage on the rail(s) and efficiency.

3) If you get a higher rated (watts) PSU, it doesn't mean it will use more power than a lower rated PSU at the same load. That will depend on the actual load on the PSU, and its efficiency. As you would expect, the higher end PSUs tend to be more efficient but obviously cost more.

My favorite hardware forum ATM is at overclockers.co.uk, which would probably suite you JJ, as it discusses uk sourceable hardware.

Sorry that I can't help you out on the specifics on the USB device sfuff, but it sounds like you might be pushing it a bit with a generic 420w PSU and an 8800.

HTH JJ,
Cambo_frog

[Edited by - Cambo_frog on April 24, 2007 1:06:42 PM]

Quote: believe that your PSU load is not that relevant - since the PSU contains a transformer, it will always suck the same amount of current, unless I'm mistaken (because there is two separate circuits). So you'd better watch the global load of your computer

What I've seen seems to disagree, but my knowledge of physics doesn't allow me to say why [lol]

This blog uses something like this to measure how much is really being used.

Seems to suggest that my Vista box which is currently idle with only MS-Word open would be using a fraction of the 580 watts the PSU is apparently able to deliver...

Quote: Having the PC running 24/7 with such a PSU would probably not hurt my bill that much, but hell, that's a good slap in the face of global warming. I guess we have to take care of this.

Yes, I'd considered much the same point.

George Monbiot's book, 'Heat,' comments that mankind developing more energy efficient electronics doesn't result in us reducing our use of energy as we just find more things to do for a similar amount of energy usage. The toaster in my kitchen plays sounds when the toast is done and has a blue LCD display on it - whats wrong with the simple mechanical toaster? [grin]

Quote: 1) Don't skimp on the PSU when using other high end components

Oh, undoubtedly the single golden rule of constructing your own system. Both my systems now have high-end branded PSU's - having the 420w generic PSU wasn't my choice as such, just came with the PC when I originally bought it!

Quote: My favorite hardware forum ATM is at overclockers.co.uk, which would probably suite you JJ, as it discusses uk sourceable hardware.

Thanks for the recommendation - I'll see about dropping by to see what I can pick up.


Cheers,
Jack

Quote: Original post by jollyjeffers

Quote: believe that your PSU load is not that relevant - since the PSU contains a transformer, it will always suck the same amount of current, unless I'm mistaken (because there is two separate circuits). So you'd better watch the global load of your computer

What I've seen seems to disagree, but my knowledge of physics doesn't allow me to say why [lol]

Well, for anybody who really wants to know, have a read. However the answer is that the amount of current drawn by the PSU depends very much on the power used in your PC. Wikipedia doesn't seem to have any efficiency figures at first glance, but if my physics teacher at school was right (and my memory is accurate), then it should be over 98%.

I don't really know about the stability issue, but at least for the graphics card it wouldn't surprise me because I suspect they push the noise limits fairly hard, and if the supply voltage drops off (which is what it will do if you draw too much current), that could cause problems.

For what you're running I'd get a 750W PSU. All those drives, the 6800 & the old CPU are probably all starving.

The only "real" data I know:
If you have an 8800 you should have at least a 750W PSU. If you have 2 8800s in SLI you need a 1000W PSU. I'd reccomend the PC Power & Cooling PSUs, they're pricey but are the bees knees of PSUs

-me

Quote:

Quote: My favorite hardware forum ATM is at overclockers.co.uk, which would probably suite you JJ, as it discusses uk sourceable hardware.

Thanks for the recommendation - I'll see about dropping by to see what I can pick up.


Cheers,
Jack

HeHe,
Check out the threads concerning the the R600 / HD 2900 XT( for a laugh, if nothing else ) in the "Graphics Cards" section.

[Edited by - Cambo_frog on April 24, 2007 4:39:06 PM]

To determine whether you're over-drawing your PSU you could check out hardware monitoring software that reports terminal voltages on the motherboard. (For example, if you have an Intel-based system at least. If you observe a significant drop (say, 10%) from the nominal voltage, then it's probably a sign your PSU can't provide enough power to the system.

Could be but you should get a warning message from the OS though? Also I know I had a firewire card for my laptop that wouldn't work unless it had an external AC power plugged in since it drew more power than the port could provide. Your hardware manual should tell you that though.

When you start a Windows XP-based computer that has one or more USB devices attached, or you plug a USB device into a powered USB hub, one or more of these devices may not work. These USB devices may be attached to a Windows XP Service Pack 2-based computer or to a Windows XP Tablet PC Edition 2005-based computer. You may not receive an error message in this scenario. Or, you may receive the following error message:
USB Hub Power Exceeded
Or, when you start your computer and connect additional USB devices to the computer until the total power consumption of the USB devices is more than the available power from the USB hub or port, one or more of the USB devices may stop working. Then, you receive the following error message:
USB Hub Power Exceeded
Similarly, if you then restart your computer with the same configuration, the same USB device or devices do not work, and you do not receive an error message.

Anyways, as far as your 8800 card goes you must've got a bum card since it actually uses about as much power as a 6800 card under load approx 200W! A single 8800GT anyways. Or you PS didn't provide enough rail power for the vidcard.
But yeah unless you have a quality power supply you are probably pretty close your PS capacity at max load with all that hardware!
In this article they use a fancy $800 kit(Extech 380801 and 380803
Appliance Tester/Power Analyzer) to measure a pc energy usage here.
But as you can see there really is no need for 1000Watt powersupplies unless you are going to use 3 videocards since even the most power hungry vidcards(the old ATI X1900 and new Nvidia GTX 280) only suck up 500W at max load.
Anyways, if you are concerned with the saving the planet and electricity I suggest getting the newest tech like 45nm Intel with speedstep whose power consumption is way less than the ovencooker P4's back in the day. Oh and make sure you use surgeprotectors and turn them off when not using stuff!
Also the new power supplies are way more efficient and you can get buy 80plus green ones they call them. Plus I've seen the new harddrives coming in green boxes saying green terabyte drives or something since they consume so much less power too. I can immediately tell in my own system by how much more quiet it is compared to older system that sound like hair dryers and wasted so much energy and heated up the room!
More power saving tips:

Ready to pick up your stake, take a stab at saving electricity and fight vampire power? Lucky for you, the battle against this energy waster comes down to two tactics:

1. Identify which electronic devices drain power when not in use.
2. Replace these electronic items with energy-efficient devices or cut off power when you aren't using them.
If you're not using an electronic device, unplug it -- that's the blanket approach to fighting vampire power. You can make this step even easier with a surge protector or power strip. Plug multiple items in the strip and simply turn it off when you're not using the devices. If the strip is off, you don't have to worry about leaking electricity.
if enough people become aware of the problem and take steps to prevent it, a vast amount of power and natural resources can be better used.