500W university room power rating

[megajames]

Hey guys

I hope to be going off to university this September, but a bit of reading has revealed that my room's power rating will be limited at 500W:

"...over 500 watts will fuse your own and other study bedrooms as well. For safety, the 13 amp plugs used on small appliances in study bedroom should be fitted with 3 amp fuses."

I'm concerned about what this will mean for my potential new PC. Firstly, I know that really high-end rigs can equal massive power requirements, so there's one issue: are there ways to reduce the necessary power for my PC.

And secondly, this sounds like a PC with a 500W PSU would be risky... I wouldn't want to have the PC on idle and then turn on the printer, only to smell burning - do you think I've understood that right?

Thanks

[Clunk]

You can easily hit 500w with a gaming rig, but for most people, its not going to be close that.

You can stick to dual core, or even single core. Dont overclock. Underclock the CPU. Get an efficient PSU. Use power saving modes to their fullest potential. Get a smaller monitor. Have one bigger hard drive instead of several smaller ones. Use lower powered fans, and a fan controller.

Laptop perhaps?

Theres probably loads more, but I'm tired

[Phil_P]

There arn't many PCs that will draw anything like 500Watts, regardless how powerful the PSU may or may not be. An average PC will probably draw 300W or less.

There are steps you can take to minimize power usage. Firstly make sure you have a modern PSU rated at 80% plus efficiency. A PSU won't convert all the power it draws from the wall into output power. For example, if your PC needs 300 W and your PSU is 80% efficient, then it will need to draw 375W from the wall to deliver that 300W to your PC. Running at full load and/or gaming also draws more power as you load the system.

Next, a large 19" CRT screen can draw 100-150W whereas a comparable TFT screen will draw significantly less, so consider a flat panel monitor if you don't already have one.

If you have a quad core system with high end graphics card(s) and a huge CRT monitor then you're likely going to be in trouble. Otherwise, most setups should squeeze in as long as you don't try to boil the kettle or plug in that electric heater at the same time

[Phil_P]

Laptop perhaps?

Very good suggestion

My Sony Vaio Core 2 Duo lappy only has a 91Watt PSU brick (19.5v, 4.7A) so that gives you an indication of how little power they use.

[CrazyMonkey]

There arn't many PCs that will draw anything like 500Watts, regardless how powerful the PSU may or may not be. An average PC will probably draw 300W or less.

Seconded, i doubt it will pull more than 350W from the wall.

[megajames]

Hmm, very interesting (and damn quick) responses. I'll be able to use all this when looking at my hardware options.

I'd like to step back a minute, and get down the way to figure out the maximum power drawn by my PC. How's this:

(PSU power rating / efficiency * 100)
+ Monitor power rating
+ Power rating of any other hardware that has its own power cord
= PC's total power draw at full load?

EDIT: Or with a laptop, just
(PSU power rating / efficiency * 100)
+ Power rating of any other hardware that has its own power cord

[staffsMike]

Most laptops come with 65 - 95w power supplies so you are never going to have trouble there.

Dells XPS 710 is supposed to come with a 375w power supply which runs a core 2 duo system with an 8800GTX..im not suggesting buying one of those but giving you an idea of the kind of system which can run off such a power supply

Monitors can use as little as 50w but never much more than 80w and thats for 20 -22" ones so you shouldnt really struggle to get a decent pc and monitor running well below 500w..

..maybe just knock the monitor off when you want to print

[bwgames]

I wouldn't worry - I had a similar thing at uni and it never blew, even when I had the kettle on and computer and a all in one printer.

If you're really concerned, go to maplin and get a "Energy meter" for £15, that way you can get a good idea of what your current power usage is...

For comparision, I have two computers, one of which is quad core etc, 24" TFT, routers, and various other electronic bits and bobs and my total power usage is ~300W.

[Phil_P]

Hmm, very interesting (and damn quick) responses. I'll be able to use all this when looking at my hardware options.

I'd like to step back a minute, and get down the way to figure out the maximum power drawn by my PC. How's this:

(PSU power rating / efficiency * 100)
+ Monitor power rating
+ Power rating of any other hardware that has its own power cord
= PC's total power draw at full load?

Unfortunately, it's not quite that simple, but you're along the right lines.

(PSU power rating / efficiency * 100)

OK, so I have a PC that has a 375 Watt PSU and it's 80% efficient. My PC can draw up to 300 Watts as we saw in my example above. Now, suppose I decide to upgrade my PSU to a 750 Watt model - is my PC using any more power - NO, I just have a higher rated PSU that's capable of delivering more power if needed. So the Wattage of your PSU isn't in any way directly related to the amount of power that your PC will actually consume other than it needs to be high enough to cope.

As a VERY VERY APPROXIMATE rule of thumb, we normally recommend a PSU twice as powerful as what the system will likely use/need so you're not running your PSU flat out and stressing it to it's limits. It's a bit like a car - it has a top speed of say 120mph, but you'll soon wear out the engine if you constantly drive it flat out so you drive it well within it's limits and it lasts for ever.

Hope that makes it a little clearer for you.

[megajames]

I'm glad to see so many people saying that 500W is by far enough, haha.

I'm definitely going to need a laptop of some variety to take into lectures etc., though admittedly I hadn't considered one for gaming as well - in the past I've avoided buying all my kit pre-assembled by a manufacturer.

What was more likely, but by no means certain, is me getting an old laptop from somewhere for superbudget cost, and spending more on a good desktop. However, you've got me interested... What other reputable high spec laptop manufacturers are out there, in addition to Alienware or Dell XPS?

And Phil, would you say the line

(PSU power rating / efficiency * 100)

needs replacing with something like

Max power rating of Graphics card,
Processor,
Motherboard,
RAM,
Hard drive(s)

which I'd find using information I from hardware specs on the internet?

The tip on the power meter is a good one bwgames, and it's good to hear from someone who managed easily in this situation. I suppose I shouldn't really need to get a power meter considering the responses in this thread so far, but perhaps better safe than sorry might justify me buying one anyway, hehe.

And staffsMike, that's a good demonstration of power usage by a PC, thanks.

edit: Just seen Vista's obviously been subsidised on the Alienware site.... Guessing I could get it and save £32, then just install XP on it right?

..second edit: will I be able to overclock alienware/xps systems?

[fat jez]

Seconded, i doubt it will pull more than 350W from the wall.

That's about what mine draws, running flat out.

*edit* forgot to say, that's measured with a power meter in the plug socket.

cheers,
Stephen

[Phil_P]

And Phil, would you say the line

(PSU power rating / efficiency * 100)

needs replacing with something like

Max power rating of Graphics card,
Processor,
Motherboard,
RAM,
Hard drive(s)

which I'd find using information I from hardware specs on the internet?

A quick solution is to use an online PSU calculator such as this one:

http://www.extreme.outervision.com/psucalculator.jsp

It's not as accurate as measuring at the wall with a meter, and probably over estimates (or more accurately will give you a reasonable estimation of the MAX power draw under any circumstances), but it does give you a reasonable idea what current individual components may draw.

[Pob255]

.second edit: will I be able to overclock alienware/xps systems?

If you're still talking laptop, No.
Well at least I very much doubt it, I've not had the chance to get at an alienware/xps laptop, however I've never seen a laptop with settings in the BIOS to overclock.

[staffsMike]

Alienware overclock for you..pretty sure you can do it yourself also.

Dell..not on your life

[megajames]

If you're still talking laptop, No.
Well at least I very much doubt it, I've not had the chance to get at an alienware/xps laptop, however I've never seen a laptop with settings in the BIOS to overclock.

Yeah, I was thinking laptops. Not surprising really, heh.

EDIT: Ah ok Mike, then alienware have got one up on Dell already.

[aidanjt]

500W is a lot of juice, you wont use that much really.. But it sounds as if the university should have hired a competent electrician when the dorms were being wired and not skimp so terribly.