i am helping a friend to upgrade his computer
we have replaced just about everything except the power supply

is a standard 230v power suuply sufficient for an Athlon 1300 chip and a G-force 4?

and if it isn't, what are the likely symptoms of a system struggling with insuficient power?

many thanks

Whats the power output of the PSU? There are PSUs that will supply 230W and there are ones that will supply 530W - one hell of a difference.

One of the first things to be effected by a PSU that can't supply sufficient power is the memory, the PSU will be supplying incorrect voltages as the current is too high. It might be worth having a read up on somewhere like http://www.tomshardware.com or http://www.anadntech.com

cheers

Jamie...

I buy custom power supplies from http://www.pcpowerandcooling.com/home.htm
very good power supplies. I've been running the Turbo-Cool 425 on my linux workstation (Athlon 900 & Geforce 2 Ultra) for 2 years now, it's solid. The box runs 24x7.

When shopping for a power supply make sure you check it's specs properly. For a system like the one you're talking about you'll want a PSU that can supply around 16A on the 12v rail. If you're buying a good quality name brand PSU (which you should be) then you'll be able to find those specs on the manufactures/retailers website or on the box itself. If someone is holding a gun to your head and forcing you to buy a generic PSU (which would be a very unfortunate situation) then have a close look at the label that you'll find on all PSU's.

This is more important these days not only because of how grunty systems are getting and the fact that CPU's draw thier power from the 12v rail, but also because HSF's, case fans and those fancy cathode tubes that all the young blokes are into draw from the 12v rail as well. It's about more than the total wattage. You need to make sure a PSU has enough power where it counts.

This is just a very basic overview in case you can't be bothered reading the excellent and far more comprehensive guide at the site you'll find a link to below

http://firingsquad.gamers.com/guides...ly/default.asp

I've been buying Enermax PSUs lately as they seem to be only decent brand readily available. Nice rigs, but it hurts to pay $70 for just a PSU when you see cases with PSU for $45 everywhere.

Excellent advice so far. Rav's recommendation for 16A on the +12V rail I would treat as a minimum. You can calculate your own requirements using a guide from AMD here:

http://www.amd.com/us-en/assets/cont...docs/26003.pdf

If you go through their example system, you can see 14-15A is needed on the +12V rail. I compiled a comparison of AMD's example system and its power requirements against AMD's recommended power supply limits, and the outputs (in Amps) of some commonly available units:

_____________________+3.3__+5V__+12V
AMD Example System_____6.9__17.3__14.2
AMD Rec Supply_________28___30___15
Generic 300W___________20___30___10
Generic 400W___________24___35___12
Antec SL300S___________20___30___15
Antec SL400S___________28___38___18

AMD's example system was for a high-performance system based on an XP2100+. It's interesting to see how little power AMD considers is needed on the 3.3V and +5V rails compared to how marginal it is on the +12V rail. But it does show that you need to be discriminating when shopping for power supplies, and you need to make sure that the one you buy can handle the load on the +12V rail. It would seem most power supplies can handle the lower voltages no problem, even the generic ones. Note how the generic 400W one doesn't cut it. You really need to go for quality.

An example of a power supply-caused problem: My friend had her brand-name computer upgraded with 64M extra memory and a new 40GB hard drive (old one out, new one in). The power supply was 110W (!!!). The computer would not boot correctly, with hard disk thrashing noises eventually resulting in an error message about not being able to find a hard disk, or one was found, but it is damaged. In about one go in five, it would boot OK, correctly detecting the drive. This behaviour disappeared when the power supply was upgraded.

Thanks for taking the time to present all that information geoff_f. You're a legend

Rav, you're welcome. I did a fair bit of research before lashing out and buying my last power supply. My own computer, and my daughter's, was having what could have been power supply-related problems, and I suppose I needed to convince myself that the outlay of the extra money was warranted. Well, I was convinced, and the new power supplies fixed the problems completely. Up to that stage, my computer had a generic 400W supply, and my daughter's had a generic 300W one (both AMD). Having collected all the info, it was simple to post it here. This question just cried out for this info, so I posted it.

This is what I like so much about LQ - people helping each other - it's great.

well

i never did realise that it was all so complex
just for a power supply i have to learn electronics (?!!?)

upshot

we went for a 400watt power supply as there were no 300's
the shop assured me it would adequately power a 1300chip

had to remove the (very cheap) g -force 4 as it was making the pc wildly unstable

final problem...

si soft sandra reports the mainboard as too hot (74 deg C)

any further ideas??

Syntax motherboard
AMD 1300
384MB SD RAM
floppy
cd
DVD/CDRW


(...muttet mutter take up up sheep farming
mutter mutter damned electricity
mutter mutter abacus)

How hot is the CPU running? The only real solution to cooling is moving hot air out... You got the capacity to add a couple more fans to your case?

cheers

Jamie...

Salparadise, what does the sticker on the side of the power supply case give as the output (in Amps) for the +3.3V, +5V and +12V rails?

the cpu is running at about 35-52C

the case is huge, room for at least two power packs and room for up to 6 cd drives
so yes, there is room for a further fan

as the pc is at it's owners house and I am not
i cannot currently answer the question about voltages

it is a tsunami 400w power pack

Ahhh. let me guess. the motherboard is way down at the bottom and the PSU is up at the top? You might want to have a look at where the air comes in to the box and maybe get another fan either pump some air into the case and force some circulation. If it's a half-decent brand-name case you should find out if the mfr has some images of it on their website.

You may also want to check the temperature of the drives as well. I've cooked one due to a poorly ventilated case.

[rant]

No, but if you are going to be building your own system(s) you need to learn a few things about the components you are going to be using. If you don't, eventually you'll make a mistake, or overlook something, or perhaps you'll end up here one day asking why your system keeps spontaneously rebooting for no apparant reason (which to answer one of your original questions can be a symptom of an inadequate power supply).

It's not just about learning a bit more about PSU's. It's about realizing that what people think they already know about them is inaccurate. Lets say your friend has a good 300w PSU which happens to have 15A on the 12v rail. He has no problems whatsoever. Now lets say that you're about to build a similar system and you choose to play it extra safe by picking up a generic 350w PSU. What you might not know is that there are a lot of 350w PSU's out there that only have 14A (or even less) on the 12v rail. So, you think you've bought a more powerful PSU, but in actual fact it is inferior because it doesn't have enough power where you NEED it.

You don't need to learn electronics. All you need to understand is that it's important to look at the label (or the specs) to find out how a PSU distributes it's power over the different rails. Almost all modern PSU's will have enough power on the 3.3v and 5v rails so you only really need to check the 12v rail. The link I provided has a simple table that you can use to estimate your total power requirement for each rail so you can choose a PSU accordingly.

The retail arm of the computer industry unfortunately enjoys a much lower level of expertise than almost any other industry I can think of. That's because you're hardly ever speaking to a technician. In fact most smaller computer stores don't even employ technicians. You just get someone who is good at putting systems together, and that's something anyone can do with enough practice. With bigger stores, you don't get to speak to technicians either because they are all out the back with lots of work to do. If you're lucky and you do get to speak to a technician, chances are you might end up having to explain something to him to get your question answered anyway. This is because they generally aren't in the loop the same way the real enthusiasts are. Not only that, they can be just as lax as anyone else. We have a saying over in Australia. "She'll be right mate". It perfectly describes the tendency to think that everything will be ok when there is no concrete evidence to support that conclusion (or even when the evidence might actually suggest otherwise).

The point is that the only way you can be sure about anything is to learn about it yourself, and when it comes to putting together your own system, you don't have to learn that much (but you probably do need to want to).

[/rant]

Just as an addendum, the most important thing to pay attention to is the TCO rating of the PSU, or Total Combined Output. This is much better than the meaningless wattage rating on the side of the PSU. TCO (if I remember correctly) is the combined wattage output on the 3.3 and 5v rails. Those 2 rails power your CPU and memory (along with a half dozen other pieces) and their rating is very important. I suggest a TCO of at least 230. As for the 12v rail, this normally powers your HD and CDrom motors, and any system fans and your floppy drive. It is still Important, but the TCO is the big one to watch.

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