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Computers & Hardware => PC Hardware => Topic started by: renluop on February 03, 2017, 04:51:05 PM

Title: PSU ratings?
Post by: renluop on February 03, 2017, 04:51:05 PM
My old Dell computer and the one before it had PSUs rated @ 300 watts. I think I need a replacement soon and a couple of HP Desktops in my price range have 180 watt PSUs. Should I avoid?
Title: Re: PSU ratings?
Post by: broadstairs on February 03, 2017, 05:36:59 PM
It all depends... if you intend to install a load of HDDs in it then 180watts is not going to be enough, if however you only intend running it as delivered with no additions then they should have spec'd the correct PSU for the machine.

I always err or the high side when replacing PSUs and always buy good quality, my desktop currently has a 500watt PSU but it a home build and I spec'd it for what I intended to install in it.

Stuart
Title: Re: PSU ratings?
Post by: parkdale on February 03, 2017, 06:15:51 PM
How much are you intending to spend? As Broadstairs noted most pre built desktops run on very tight margins with little room for improvements.
Also there are some very naughty power supplies sold very cheaply.
Please let us know what you want, would like.

Edit:- found this...

https://www.novatech.co.uk/products/pcs/brandedpcs/desktoppcs/b-nti142.html
Windows 7 pro coa £5 from Fleabay etc
Title: Re: PSU ratings?
Post by: renluop on February 04, 2017, 10:34:48 AM
What I have now, OS upgraded from Win 7. I don't think a discrete GPU is a particular necessity. I intend to use existing monitor.
Quote
Operating System
   Windows 10 Home 64-bit
CPU
   Intel Core 2 Duo E7500 @ 2.93GHz   42 °C
   Wolfdale 45nm Technology
RAM
   4.00GB Dual-Channel DDR3 @ 532MHz (7-7-7-20)
Motherboard
   Dell Inc. 0K83V0 (CPU 1)   56 °C
Graphics
   DELL ST2210 (1920x1080@59Hz)
   1024MB ATI Radeon HD 4300/4500 Series (ASUStek Computer Inc)   52 °C
Storage
   596GB SAMSUNG HD642JJ (SATA)   30 °C
   465GB Western Digital WD My Passport 0740 USB Device (USB (SATA))   30 °C
Optical Drives
   PLDS DVD+-RW DH-16AAS
   WD Virtual CD 0740 USB Device
Audio
   High Definition Audio Device

Max spend £350.

As to examples: thanks,but with that I'll pass. I would look at a refurb, but it would need to be much better than that. Anyhow, whilst Novatech years back had a good reputation, now it deems not so.
Title: Re: PSU ratings?
Post by: Bowdon on February 04, 2017, 11:10:14 PM
I recommend overclockers. They are good on returns too. There is also a forum on their site as well.

https://www.overclockers.co.uk/pc-components/power-supplies/up-to-500-watts (https://www.overclockers.co.uk/pc-components/power-supplies/up-to-500-watts)

There is a 500w PSU for £32.99 on that page. As the others have said its always better to overshoot on PSU's.
Title: Re: PSU ratings?
Post by: Chrysalis on February 04, 2017, 11:41:48 PM
180 watts sounds very low, I would avoid it.

https://www.overclockers.co.uk/xfx-xt-series-400w-80-plus-bronze-power-supply-ca-021-xf.html
Title: Re: PSU ratings?
Post by: sevenlayermuddle on February 05, 2017, 12:26:51 AM
Obviously, a PSU needs to be capable of supplying peak requirements.   PC manufacturers ought to be able to ensure they do, for the configuration as shipped.  But is there any advantage in a PSU that exceeds requirements?   I'm not sure there is. 

My only experience of a PSU  that died prematurely turned out to caused by low quality aluminium electrolytic cap's, it died an ungraceful death just outside the one year warranty.   But that was 7 years ago and, with all caps replaced, has never missed a beat since.

Moral is, a PSU that meets (no point in exceeding) requirements should be fine, as long decent quality components are used. :)
Title: Re: PSU ratings?
Post by: roseway on February 05, 2017, 08:06:54 AM
I don't think I agree with the above. A higher rated power supply will run cooler, and temperature is a major factor in the life of electrolytic capacitors. Also, spare capacity means that less is required of the cooling fan, so it's potentially quieter.
Title: Re: PSU ratings?
Post by: ejs on February 05, 2017, 08:36:02 AM
I think at some point though, the PSU may be operating at such low output it will be running at less than optimum efficiency. I ended up getting a 700W PSU which was on offer and so around the same price as some 400-500W ones I was looking at. It's very nice and quiet and modular, but also complete overkill for a PC that IIRC uses about 70W (measured at the mains plug).
Title: Re: PSU ratings?
Post by: sevenlayermuddle on February 05, 2017, 08:43:02 AM
Should a higher rated  PSU really run cooler?   Surely the heat produced is simply a reflection of the PSU's efficiency, and I don't know any reason to assume that a higher rated PSU would be more efficient.   :-\ 

I'd not be surprised in fact if an overrated PSU was actually less efficient, owing to operating outside of optimum range.

Arguably I suppose the bigger PSU may perhaps have a bigger fan that would be better at cooling itself down, but that big fan would itself be consuming more power and so generating all the more heat.

But it's an interesting angle of discussion,  not sure who's right.
Title: Re: PSU ratings?
Post by: sevenlayermuddle on February 05, 2017, 08:46:18 AM
I think at some point though, the PSU may be operating at such low output it will be running at less than optimum efficiency. I ended up getting a 700W PSU which was on offer and so around the same price as some 400-500W ones I was looking at. It's very nice and quiet and modular, but also complete overkill for a PC that IIRC uses about 70W (measured at the mains plug).

Agree with all of that, which crossed with my previous post, didn't mean to ignore it.   ::)
Title: Re: PSU ratings?
Post by: JGO on February 05, 2017, 09:06:44 AM
A higher rated power supply will run cooler, and temperature is a major factor in the life of electrolytic capacitors. Also, spare capacity means that less is required of the cooling fan, so it's potentially quieter.

Agree a higher rated PSU will run cooler, BUT most of the dissipation should be in the useful load anyway not the PSU itself. I wonder is a larger system fan a better investment ?
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 10:22:30 AM
I'm mulling over your replies, but these are the two HP offerings I am looking at. Most usage is routine with low to moderate photo editing.
How do they fit with your thoughts?
Title: Re: PSU ratings?
Post by: broadstairs on February 05, 2017, 10:38:19 AM
Never been a fan of HP systems but that's just me. I suspect either would be perfectly acceptable for photo editing, if you do any video editing and rendering then more CPU cores to spread the workload would be noticeably beneficial. That apart my reservation would be how many extra HDDs would you intend adding? This might stress the PSU. There is a lot more to deciding on which PSU to use other than the overall rating, there is quite a lot of reading material available on the net about how to size a PSU and how to interpret the detailed specs (if available) of the PSU you consider. The fact that you mention photo editing suggest you use digital photos to quite an extent and I guess you might need at least one more HDD for photo storage.

Stuart
Title: Re: PSU ratings?
Post by: sevenlayermuddle on February 05, 2017, 10:51:32 AM

I no longer use Microsoft OS, so have not got any 'feel' for what kind of performance to expect.

Kind of echoing Stuart's comments, from a different angle.... One thing does strike me about both systems... 500GB disks?  That is not a lot in today's terms.   IMHO this would be worth thinking through... is the system used for storing photos as well as editing?   And are you likely to buy a new camera (with more pixels) at some point, which would increase storage even more?   Note though I am not saying it's bad,  just saying "think it through".  Having thought it through you may conclude that 500GB is fine, and I would be in no position to disagree.  At the end of the day you could always attach an external disk for more storage, but that would add a few watts to power requirements.

Memory is also relatively modest by today's standards, at 4GB. Not sure whether photo editing tools are particularly memory-greedy, I think they might be? Personally, I'd want to make sure it is at least upgradeable if it proves inadequate.

I've not had any HP desktops, but I have had a couple of their pretty cheap 'proliant' servers.  Always seemed very well made.
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 11:15:17 AM
Never been a fan of HP systems but that's just me. I suspect either would be perfectly acceptable for photo editing, if you do any video editing and rendering then more CPU cores to spread the workload would be noticeably beneficial. That apart my reservation would be how many extra HDDs would you intend adding? This might stress the PSU. There is a lot more to deciding on which PSU to use other than the overall rating, there is quite a lot of reading material available on the net about how to size a PSU and how to interpret the detailed specs (if available) of the PSU you consider. The fact that you mention photo editing suggest you use digital photos to quite an extent and I guess you might need at least one more HDD for photo storage.

Stuart
I assume you mean internal HDD rather than external. Is my assumption correct? Can you give any links to the best of that readable stuff,please? :)
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 11:53:11 AM
I no longer use Microsoft OS, so have not got any 'feel' for what kind of performance to expect.

Kind of echoing Stuart's comments, from a different angle.... One thing does strike me about both systems... 500 GB disks?  That is not a lot in today's terms.   IMHO this would be worth thinking through... is the system used for storing photos as well as editing?   And are you likely to buy a new camera (with more pixels) at some point, which would increase storage even more?   Note though I am not saying it's bad,  just saying "think it through".  Having thought it through you may conclude that 500GB is fine, and I would be in no position to disagree.  At the end of the day you could always attach an external disk for more storage, but that would add a few watts to power requirements.

Memory is also relatively modest by today's standards, at 4GB. Not sure whether photo editing tools are particularly memory-greedy, I think they might be? Personally, I'd want to make sure it is at least upgradeable if it proves inadequate.

I've not had any HP desktops, but I have had a couple of their pretty cheap 'proliant' servers.  Always seemed very well made.
500GB? My existing same capacity is no where near full, as I weed out, and have some of the photos on an external drive, so it seems profligate to get more than I need. Am I stupid for minimal cost? Cameras' megapixel counts are a bit of marketing hype. Actually the predecessor to the one I have had 18M; mine has 12M. On a small sensor there was more noise @18M.

Extra watts needed for external drive; wouldn't those be limited to when loading and retrieving, and so not permanent. For those times would the increased power be a big factor?
Title: Re: PSU ratings?
Post by: ejs on February 05, 2017, 12:43:04 PM
Depends on if the external hard drive has its own power supply or not.

Hard disks don't really use that much power, they might have a peak requirement of about 25W for a very short time when they spin up. My current 3TB storage hard disk claims to typically use 5.4W during read/write operations. It's a "low energy" model, but then all the big cheap disks tend to be the low power not designed to be really used types.
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 01:07:13 PM
The ones I have are USB powered.
Title: Re: PSU ratings?
Post by: sevenlayermuddle on February 05, 2017, 01:16:10 PM
I wasn't suggesting that a massive headline pixel count is a good thing, I agree it sometimes is not.  But manufacturers will follow whatever fashions are followed, which may mean higher pixel counts in future.

I've just recently got a new camera myself, which sports a 20 megapixel sensor.    It supports a 'Raw' mode as well as producing jpg images and, for now, I'm saving both.   That means about 30-40MB of data for each photo...   

I've already made quite a hole in the 64GB sd card that I initially stuck in the camera.  Admittedly though, I'm still playing with it trying to learn its capabilities, which might mean a whole afternoon  taking dozens upon dozens of pictures of the garage at different settings so I can compare the ffects. :D
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 01:29:47 PM
Completely OT, but I'm wondering what pixel rating or eyes would have were they cameras with our current processor with its on board graphics. ;D
Title: Re: PSU ratings?
Post by: parkdale on February 05, 2017, 02:27:16 PM
Hi Renloup,  try this as it's in your price bracket, and with 1 Tb 8Gb ram.
http://www.ebuyer.com/749503-hp-460-p035na-twr-desktop-w3b45ea-abu
More Ram = better photo editing.. Windows 10 expects min 4Gb.

Power supplies generally are designed to be at their most efficient running about 80% capacity, thats why Hp et al tend to not go too mad with watts.
If you're going to add Graphics cards and bigger harddrives then that's where the extra power is needed.

Used this tool to calculate my system http://powersupplycalculator.net/
Mine at idle 71 Watts
At load 268 Watts
Recommended supply 365 Watts
My Power supply is rated at 650Watts Corsair TX650v2 (made by Seasonic)
My graphics cards is by far the biggest culprit in my system Nvidia  GTX960 4Gb


 
Title: Re: PSU ratings?
Post by: renluop on February 05, 2017, 04:35:03 PM
That calculator looks interesting, but at a quick glance the CPU of the HP system is not listed.
Title: Re: PSU ratings?
Post by: ejs on February 05, 2017, 04:56:30 PM
https://ark.intel.com/products/90734/Intel-Core-i3-6100T-Processor-3M-Cache-3_20-GHz

I don't think you can add much to that HP.
There's a picture of the motherboard at http://support.hp.com/us-en/product/hp-460-p000-desktop-pc-series/10734573/document/c05240040/

It does have a slot for a graphics card, but I can only see 2 SATA ports on the motherboard, so I don't think any internal drives can be added.