PSU Advice

[barry2811]

I finally upgraded my CPU and went to the dark side. I'm now running a 4670K at stock on a Z87 board.

I have 2 DDR3 DIMMs (8GB), an AMD Radeon HD6870, SSD, 2 x 1TB HDD, 1 x 3TB HDD, USB powered card reader, wireless PCI NIC (which I'm not adverse to removing), Noctua NH-D14 CPU Cooler (2 x fans), 200mm front case fan and a 120mm exhaust case fan.

Powering all that is a Corsair HX-450 which has always been (and still is) fine.

I'm flogging my old CPU and motherboard and considering selling my 6870 as well. I would then be interested in a 280X.

My question is, would my HX450 have enough juice for all the above, but with the 6870 exchanged for a 280X? I think I would be cutting it fine?

[Willzzz]

Yeah that would be cutting it very fine.
You'd probably get away with it, but it would be a risk.

[barry2811]

They were my thoughts. What would you think about maybe a 270X instead of a 280X?

[jim]

PSU should be fine. Check out this for comparison: http://hexus.net/tech/reviews/system...-gamer/?page=6

236W at 3D load.

Even this overclocked Titan monster could run comfortable with a 450W PSU: http://hexus.net/tech/reviews/system...-titan/?page=6

[Willzzz]

Yeah you could go for the R9 270 as a nice cheap option, it should run most games just fine as long as you don't max settings
Or if you really want top end performance you could get a GTX 770.
I mean in theory a 280X *should* be just fine, normally @stock you'd expect low 300s, but there have been cases where power draw has exceeded 450W.

How are you finding performance with your current 6870?
This on 1080p I presume?

[Willzzz]

236W at 3D load.

But that's a 760, which would be a fine choice for a 450W system and a decent upgrade over a 6870.

A 280X should be fine, but it is possible to exceed 450W in a worst case scenario.

[jim]

But that's a 760, which would be a fine choice for a 450W system and a decent upgrade over a 6870.

A 280X should be fine, but it is possible to exceed 450W in a worst case scenario.

And if you look at the second link, 320W for a Titan. It will be fine.

[Willzzz]

What does the power draw of a Titan have to do with this?
I don't think that is one of his options.

[jim]

You said that a 760 drawing 236W proved nothing, because a 280X could exceed 450W. I've demonstrated that a Titan, which is a ridiculously over the top card, will still only draw 320W.

Are you seriously suggesting that you think a 280X will draw 130W more than a Titan?

[barry2811]

Thanks guys. The 6870 copes quite well with 1080p, but it now stands out as the weak point in my system, and is still quite saleable, so I think it is a good time to change.

The one thing that worries me is that the HX450 has 33A on the 12V rail, giving 396W for that rail. Would I still enough headroom given the number of hard drives?

[kalniel]

The one thing that worries me is that the HX450 has 33A on the 12V rail, giving 396W for that rail. Would I still enough headroom given the number of hard drives?

Oodles. Hard drives really take very little power in comparison - about 7W a drive at peak load or thereabouts.

[barry2811]

Thanks. The specs for the 1TB drives state that spinup requires approx. 30 watts.

I'm a little worried about the initial startup with everything running full whack for a second or five.

[herulach]

Thanks. The specs for the 1TB drives state that spinup requires approx. 30 watts.

I'm a little worried about the initial startup with everything running full whack for a second or five.

But at startup you have no cpu load and no GPU load. Its incredibly unlikely you'll be spinning up all your drives whilst loading the CPU & GPU 100%.

[kalniel]

As above, shouldn't be an issue as even if power saving technologies haven't kicked in yet for the CPU, the lack of load will reduce power demands and the GPU will not be drawing much either. If you're worried you can always stagger the hard drive spin ups via bios controls.

[Willzzz]

You said that a 760 drawing 236W proved nothing, because a 280X could exceed 450W. I've demonstrated that a Titan, which is a ridiculously over the top card, will still only draw 320W.

Are you seriously suggesting that you think a 280X will draw 130W more than a Titan?

Yes, not under the same circumstances of course.
Are you seriously suggesting that a system with a Titan in it will never exceed 320W?

You can't take an "Extreme SFF" system designed for lower power consumption running a single 3D game as the worst case scenario.
Hexus don't even specify whether 320W is an average or maximum.

[jim]

Yes, not under the same circumstances of course.
Are you seriously suggesting that a system with a Titan in it will never exceed 320W?

You can't take an "Extreme SFF" system designed for lower power consumption running a single 3D game as the worst case scenario.
Hexus don't even specify whether 320W is an average or maximum.

In what way is it designed for lower power consumption? It's the same CPU and GPU chip, and that's what draws the power.

And it might not be worst case scenario, but it's a very typical high-power scenario. Sure, you could probably run Prime95 and FurMark and send everything through the roof but that's just daft. If it's using 75% of the available juice during a typical high-power scenario, then it's going to be fine.

I'm very seriously suggesting that a Titan equipped system will never go above 450W unless you do something very stupid.