Upgrading a PC power supply

[News]

Child wants to fit an upgraded video card to his PC, and the card requires 400w power supply, with 500w recommended. Current power supply is a modest 300w. Replacements seem readily available, but how do I know what is required, to physically fit?

Have seen ATX style, but I haven't a clue what type of case he has, other than it is a tower. How can I tell? Presumably the wrong one will be a disaster. The holes for mains plug and fan must line up, as must fixing screws. Are cables all the same?

Thanks!

[Paul D Smith]

Check his power supply - probably says "ATX" on it. Then follow the wires, especially those going to the motherboard and note down what they look like. Check number and type going to drives and then allow for these required by the graphics card. Buy supply with similar but higher rating. Odds are, any power supply of the correct rating will fit - this is a rare case of standardization working.

You could even remove the old one, toddle down to PC World and say "I want to replace this with a whopper" and get them to open the box and check the connections. FWIW, this is probably the only thing I ever purchase at PC World because it's heavy and I normally need one NOW!

BTW, you will probably have spare unused connections. You might want to put some tape around these before your trip so you don't spend time worrying about "that connection you don't actually use".

Paul DS.

[News]

In message , Paul D Smith writes

That was quick! :-)

Have now remembered that Google is my friend, and found a picture of the existing power supply :

at the info below the images, it appears that this is a standard ATX unit. Sadly, PC World and similar are miles away (I'm in rural Aberdeenshire), so would prefer to buy online, if possible.

Something like this looks suitable (eBay link) :

are, I think, four connections in use currently - 2 x SATA, to the hard drive and DVD, 1 x 24 pin main power to the mobo and 1 x 4-pin+12v power connector, again to the mobo.

[dennis]

What card? Some of the high power cards need to use additional power connectors from the supply, some use the disk power cables. You need to check if it does and how many so that you know how many drive connectors you need on the new supply.

If it doesn't need any it will probably work with the existing supply as liteon ones are quite good. They tend to assume the supply is cheap rubbish and specify one twice as big as actually needed. Also its how much power you have spare that matters not what the supply can provide, a 500W supply is no good if you are taking 450W to run the existing kit.

[Hugh - Was Invisible]

My graphics card system requirements include "500 Watt or greater power = =

supply with two 75W 6-pin PCI Express=AE power connectors recommended"

Don't know if that means an overall supply of 500w with 150w for the =

graphics card (i.e. 2 x 75) or whethr it means graphics card could take = up =

to 150w.

It does indeed have 2 power supply leads connected to it. In any event m= y =

power supply is 750w.

Suggest the OP ensures adequate ventilation if upping the PSU

[News]

In message , "dennis@home" writes

Nvidia GTX 550 TI

Some of the high power cards need to use additional power connectors

Yes, ISWYM. The specs suggest one 6 pin supplementary power supply, which is not available from the new power supply I was looking at.

Looking again at the card, the outputs seem to be Two Dual Link DVI-I, Mini HDMI, whatever they are. His existing monitor is a standard VGA connector, which does not seem good, unless I'm missing something.

Current RAM is 3GB, which is apparently the maximum for his OS, Win 7 Home, 32 bit.

[Martin Brown]

You have to really choose unwisely to get one that won't physically fit in the allocated space. But you really need to know if the graphics card or motherboard has any particular requirements of extra power connectors. Some high end cards demand extra direct connects from the PSU as do CPUs. Also you might need to pay attention to the mixture of voltages and powers that the PSU can source (although adding an extra

100W of headroom will probably be good enough).

The internal cables vary enormously in terms of how many SATA and old style connectors they provide. Do a count on the original unit. Many modern CPUs also require a local connector as well.

Photograph the existing PSU in situ and count up how many of exach sort it has before you do anything.

[Andy Burns]

DIV-I to VGA requires only a passive "dongle", often one is supplied with the graphics card.

[John Rumm]

If its a "normal" case, (i.e. no a special low profile jobby or other small form factor) then they are a standard size.

Almost certainly ATX. AT went out over a decade ago. ATX uses low voltage signalling from the "on" button the the motherboard. AT used a physical switch in the mains to the PSU.

Cables are generally the same. There are two forms of motherboard connector - the older one with an extra four pins. The PSUs will have a detachable section on the end of the MoBo connector to cope with those.

Check the graphics card, some will have an additional power connector. The PSU will ideally need one to match. (although adaptors from a drive connector can also work)

[Weatherlawyer]

I don't understand why the manufacturer rcommends an overall power power supply.

The actual demand for the card is nowhere near the recommendation.

The wires coming out are all rated at from 2 to 15 volt IRRC (TIDTIRC) I doubt the video is going to need more than 15 v is it?

It's not actually supplying the mains tothe monitor. And how does the company know if you are intending to use multiple monitors or not?

I'm not an expert by any means but it does sound like speculation.

Something along the lines of a new and improved Windows operating system, all you rally need is a major computer upgrade and it will work just fine.

(Something like 4 GB of RAM for Vista to work like a late 20th century OS for example; or some such trumpery.)

[The Natural Philosopher]

are you honestly saying that you cant get a decent graphics performance without running what amounts to a whole aga's worth of room heater?

It is simply not POSSIBLE to dissipate 400W on a single or pair of chips. Even with fans..

I am not questioning what the makers *say*, just whether its real.

its that its thankfully a peak power rating - I guess what that means is as you crash the mothership, it needs to chew a lot of pixels and peaks out at 360W on the card..well one is tempted to buy a big 5v supercapacitor...or a battery...cos you wont run that sort of continous power without melting silicon.

ssheesh

[Brian Gaff]

I think its far more likely that the actual card will not work in the given motherboard than you will have issues with the psu myself. Brian

[Dave Plowman (News)]

Last time I looked CPC were good value for such things.

[Bob Eager]

And, sometimes, Amazon.

[Martin Brown]

Some of the fastest graphics cards have rather extreme peak power requirements and it isn't a good idea to have the PSU croak.

True enough. But 100W or more peak for each CPU/GPU chip is not at all uncommon and memory chips in fast boxes also have their own heatsinks. I have a graphics card lying around to test at the moment that would overload a 300W PSU and might well be damaged as a result.

PC is no good if it crashes each time a serious transient peak current drawing load occurs during gaming (which is by far the most demanding application). You can render video with something much less powerful.

The fastest CPU and GPU chips these days are typically not far off dissipating heat at about the same rate as a soldering iron tip. The forced air cooling and massive heatsinks are there for a reason. Fan failure can do real damage if the unit doesn't shut down gracefully.

Greener GPUs & CPUs do exist but gamers tend to push the limits.

I think child should be encouraged to learn how to DIY this stuff.