PSU

Digifrog

Digifrog

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Scott
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Halloo

I have a question for the techy PC builders. For those that helped with the graphics thread thank you. It seems one thing has led to another and I seek your advice again. Basically I want to know if my PSU will have enough grunt. As I only upgrade hardware components when needed this means that I don't do it very often.

My present set up is

400W PSU
Gigabyte Z68XP-UD4 Motherboard
Intel i7 3.7Ghz Quad CPU
Radeon HD5450 Graphics card
1 x HDD

However, things are changing. I am replacing the Radeon graphics card with an ASUS Nvidea GeForce GTX 750Ti and I will be replacing my existing HDD with a Samsung Pro SSD (120Gb). Once the HDD are swapped out I intend to format the older HDD (not SSD) and whack it back in, so I will have 2 x HDD's.

The newer system will be therefore

Gigabyte Z68XP-UD4 Motherboard
Intel i7 3.7Ghz Quad CPU
ASUS Nvidea GeForce GTX 750Ti graphics card
1 x SSD (primary)
1 x HDD (secondary)

Will a 400W PSU be enough? Or should I consider getting something with a bit more umph? If so what level?

Oh and I also have an external HDD that I turn on every now and then.

Cheers
 
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Hi there, which make and model PSU do you have? If it's a decent brand PSU with enough AMPs dedicated to the +12V rails it should be fine. The GTX 750 Ti doesn't require additional power from the PSU and I think it loads at around 120W!
 
Run your potential kit through somehting like this PSU sizing calculator. Should give you a good idea.
 
As long as it's a decent brand of PSU it'll be plenty. I run an i7 3770, an HD7750, two 3.5" HDDs and an SSD off a 450W PSU. Total draw of what you're proposing probably won't be even half what the PSU can provide, unless you start overclocking the CPU, of course.
 
I'm not sure of the brand. It looks like a EVO LABS Pentium p4 (?) That's what it says on the side so not an Antec or a Corsair.

I've just done an online calculation thing (via Corsair) and funnily enough they think I need to upgrade my PSU to a Corsair 650. Presently I am looking at a Corsair CX750 as I can get a new one at a discounted price.

I would prefer it if I can get away with not buying one at all though.
 
It should be fine. My system with an overclocked i5 processor and 2 GPU's pull less than 450W from the wall at full load (GPU and CPU). Allowing for the efficiency of the supply, that means only around 400W to the PC. The 750ti is a good low power card as well.
 
if you do manage to push the 400w psu too far the it'l fail quite spectacularly iv'e had 2 fail because of power hungry graphics cards they seem fine until do something that uses the graphics processor ( games . benchmarks etc ) luckily no damage was done to the rest of the pc

i would calculate what you think you would need and add an extra 100w to be sure which is pretty much the corsair cx750 you already have in mind
 
Your new set up should use less power than your last set up so as far as power goes you will be fine.

Having said that I never skimp on PSU's as they can do a lot of damage to other parts of your system if they go wrong.

If your looking for a new one then I would recommend going for a branded model with a single 12v rail. This doesn't have to cost the earth - I just built a system for my father-in-law and bought an EVGA 500w PSU for under £40.

The better manufacturers include Corsair, Seasonic and EVGA plus a few others.
 
neil_g said:
the system should just power down. what were they?

e: in fact it shouldn't boot at all. load on the PSU is near 100% at post.
Click to expand...

If a PSU just fails then it may just shut down. The problem comes with when they start to fail the voltage's on the rails can fluctuate.

This has a very nasty habit of killing motherboards and can damage anything else attached to it.

That's why I would recommend a single 12v rail (branded) PSU and why almost all of the better ones available are built this way.
 
Yes. PSUs can ruin motherboards and disks. Just not worth chancing it IMHO.
 
the whole single vs multi rail argument is a huge can of worms. its been done to death for years with pro camps on both sides.

a good psu should not fail spectacularly when it cannot supply the requested load. a cheaper unit maybe.
 
neil_g said:
the whole single vs multi rail argument is a huge can of worms. its been done to death for years with pro camps on both sides.

a good psu should not fail spectacularly when it cannot supply the requested load. a cheaper unit maybe.
Click to expand...

lol, yep the rail debate has gone on forever - and your right, any good PSU will be a safe option.

To get back to the original question, I would buy a new PSU. 500w would be ample for a good branded model.
 
neil_g said:
the system should just power down. what were they?

e: in fact it shouldn't boot at all. load on the PSU is near 100% at post.
Click to expand...

they were 400w psu that came supplied with a couple of tower cases nothing special

i did mention they failed because of a graphics card upgrade which wouldn't be running at 100% at post it would be doing very little until something graphics intense was going on

both psu's were the same i replaced the broken one with the second one thinking it might of just randomly failed the second one failed in exactly the same way as the first one ( same pc same circumstances )

it's a while ago on a p4 with agp graphics the card used for the upgrade was an ATI saphire x1950 pro

the psu's were fine until you wanted to do something graphics intense and when you did it didn't take long for them to fail with a flash a wisp of smoke and whats that funny smell :(

like i said no damage to the motherboard, hdd or any other part of the pc in fact it's still going strong today my daughter still uses it
 
i went over the top and got a 1000watt psu just to sort of future proof
i dont have any graphics cards
just a i7
 
For anyone reading this in teh future, its well worth investing just a few quid in a power cunsumption monitor. You can get one fro about £10 and answer your question definitively.

Heres mine flat out benching for a HW Bot competition.

541968_10200404074373043_1623943141_n.jpg



I eventually saw her peak at 1221w before I got bored of Computers and took up Photography. LOL
 
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