Why do people buy PSUs that are over 700W?

[Andaho]

It's marketing isn't it? A way to charge more money for a product and increase profits for the companies making them.

It's a lot more than marketing; It's supply and demand. The world is changing and customers want energy efficient products, if not for saving the world, for saving money on the electricity bill! - the money you can save is a lot bigger than most people think!

How many people actually find out the Watt usage of all their components in their system and work out how much Wattage the PSU needs?

I do

[joshwa]

It's a lot more than marketing; It's supply and demand. The world is changing and customers want energy efficient products, if not for saving the world, for saving money on the electricity bill! - the money you can save is a lot bigger than most people think!

How do you save money buy buyer a higher wattage PSU?

[Phil_P]

How do you save money buy buyer a higher wattage PSU?

Because most PSUs are at their most efficient at around 50% load - the region in which they are designed to work.

[Andaho]

How do you save money buy buyer a higher wattage PSU?

I don't know how you got that question from what I said, because I was talking generally and not really about PSUs, but Phil_P answered the question...

Because most PSUs are at their most efficient at around 50% load - the region in which they are designed to work.

But don't forget that 99% of the time a general use PC is idle (more for PC that is only switched on for gaming, but still idle more of the time than when it's under heavy load). So when idle, it will only be drawing 50% of the power - so for best efficency, it's still best not to go overkill with a PSU.

[Thorsson]

My OC'd Cores are in 100% use about 70-95% of the time (24/7). Not sure how many people buying heavy PSUs spend much time on "general use" only, but my bet is not a lot.

[Andaho]

My OC'd Cores are in 100% use about 70-95% of the time (24/7). Not sure how many people buying heavy PSUs spend much time on "general use" only, but my bet is not a lot.

Why's that? You got Norton Internet Security running in the background?

[Phil_P]

My OC'd Cores are in 100% use about 70-95% of the time (24/7). Not sure how many people buying heavy PSUs spend much time on "general use" only, but my bet is not a lot.

Agreed - if you're buying a quad you probably have a use for the processing power. General users and gamers are probably better off sticking with a faster C2D.

[Phil_P]

Why's that? You got Norton Internet Security running in the background?

Na - you'd need dual quad Xeons to keep Norton happy

[Saracen]

........

I've never heard of anyone that has actually had a PSU that blew and took components out with it, so it must be a pretty rare thing? - I hear lots of talk about people saying "don't buy cheap because it might happen", and seems like it's an exaggerated fear. I actually worked at a (rip-off) computer shop for 6 months last year, and saw about a dozen of PCs with dead PSUs come in, and at the shop they change the PSU for a £15 one (and charge £89 inc vat and fitting), and give it a 12-month warranty, and never got any back.

Well, I had one a brand new (3-week old) one blow and take out :-

- motherboard
- RAM
- DVD-RAM drive
- five hard drives
- network board
- an Adaptec caching SCSI raid board
- a golden sample video board that was on loan for review.

It crisped just about everything except, ironically, the CPU, which was fine. And it was a brand (Macron) which, at least at that time, had a good reputation. That £50 PSU cooked >£1500 of components.

So is it an exaggerated fear? Maybe. But that doesn't mean it doesn't happen.


My philosophy mirrors that of Phil_P et al. I aim to specify a PSU that will equate to about double the PCs typical current draw. That means that I'm operating at peak efficiency as much as possible, and that I've got plenty of leeway to cover peaks.

But power capacity isn't the only factor. There's no point in having a PSU that provides 900w if it's a cheap design, with cheap components that can't supply clean, stable power under load, and it's precisely when power draw peaks that many cheap PSUs show their weakness.

Build quality is therefore important to me, too. I'd MUCH rather pay a bit more for a quality brand, and hope to ensure decent quality components. For instance, is the cooling fan a decent design with quality bearings, or cheap rubbish with naff sleeve bearings? If that fan fails, overheating is pretty much inevitable and with it comes a near-certain PC instability with random restarts, and also a significantly higher chance of both PSU component failure and a cooked PC.

To my way of thinking, economising on the PSU is false economy, and I'd much rather spend an extra few quid (or £0 for that matter) on a quality component. If nothing else, it gives some peace of mind.

[zephod]

http://forums.hexus.net/showthread.php?t=65188

I'm not 100% convinced by that calc but its a good indicator. I reckon it gets my system as using more power than it does by about 50W...then agian, maybe its right... /me buys new psu...

[-N!CK-]

did corsair not test their 620W psu and it ran quad core, 2gig ram, and sli gtx's, not sure how many hdd's though but it was perfectly fine, can't find the link though

[notsobig]

It crisped just about everything except, ironically, the CPU, which was fine. And it was a brand (Macron) which, at least at that time, had a good reputation. That £50 PSU cooked >£1500 of components.

Wow that sucks big time. My synpathy. Doesn't home insurance cover these kind of unexpected losses? BTW out of curiosity which make was the PSU that's popped?

[Clunk]

I also had a PSU blow, and I mean blow, with a bang, pop, fizz, and it took the RAM, CPU, motherboard, CD Burner and CD Drive (plextor SCSI), an SCSI card, but the GPU stayed intact miraculously.

That was a fairly cheap case from scan in around 2000/2001 using the included PSU.

Since then, I have had several jobs in with almost identical carnage, and always the same culprit.

I know someone that had a good PSU (Enermax Noisetaker 600w) blow and take stuff with it, but that was someone that was grinding/sanding/polishing/cutting his aluminium case with the PSU and motherboard still in place You know who you are

[Saracen]

Doesn't home insurance cover these kind of unexpected losses?

Perhaps .... but the supplier's consequential loss insurance did.

But nonetheless, it's a pain in the coccyx to sort out the carnage, and the time of rebuilding.

BTW out of curiosity which make was the PSU that's popped?

Erm ....

And it was a brand (Macron) which, at least at that time, had a good reputation.

[notsobig]

OMG I need new glasses and another pint of beer Glad that it all sorted now.

[mildlyAmused]

Out of interest, would you guys recommend buying an Enermax Galaxy 1k watt PSU to run a pair of 8800GTX and a QX6850? The PSU calculator rated this (and the rest of the system I'm building) at about 944W peak load (!!!), does that sound about right?

Quick system summary:

QX6850 C2D processor (not overclocked)
4GB OCZ Reaper PC2-9200
Abit IN9 WiFi mobo
2x 8800 Ultra (not overclocked beyond what they're already at)
2x WD Raptor 150GB
2x WD 750GB
X-Fi sound card
1 (maybe 2) DVD drives

Also, daft question - buying a 1k watt PSU is going to make a difference to my electricity bill I'm sure, does this mean the PSU will draw 1k watts from the wall socket at all times, or just however much it needs?

Cheers.