Good points! Thanks for that. I have never used a dual gpu system, so i won't have too many high expectations!
I suspect I'll just end up sticking with the single rx480 until it's unusable... or rather deemed unusable by Oculus...
(Like they did with my Radeon EAH6850)
I must admit, I find the psu thing quite fascinating. All this interest in efficiency seems at odds with people looking at 1200w psu's? Like buying a BMW M5 V10 and worrying about the MPG!
I think the whole 'eco' thing is bonkers as the less electricity people use, the more expensive it will become. The suppliers will never risk upsetting their shareholders...
PSU's are also interesting due to the massive price range for similar power output and also the fact that most PC PSU's are just supplying another dc-dc psu elsewhere in the pc. The 3.3v output is probably the only output that goes directly to any digital ic's.
Any lack of regulation or excess ripple on the 12v output is dealt with in the upstream psu... (if it's designed right)
Well my first RX480 was £155 (new, with free Doom) which isn't bad. They'll be £100 in 6 months time when Vega comes out!
Re power consumption, RX480's appear to be around 170w max with peaks at 225w. That's without any overclocking, I think.
An i7700k is going to be 100w, not sure what the peak is.
I'd say that would be pushing a 500w psu a bit hard, so a 750w or 850w should take that in it's stride as you don't really want to run the limits of the psu.
The bigger question is still the fact that a 'cheap' 850w is massively cheaper than a 'high end' 500w, so even if the cheap psu is really a 650w being pushed too hard, running it at 500w should be fine.
I think if we were talking 25% price differences, it wouldn't be an issue but with cheap 850w from £30 to £50 and high end 500w at £100, it seems that the bells and whistles come at quite a price.
So you think the dc-dc on a pc mb is just a potential divider and just lowers the voltage without regulating it?
Do you also think that an Intel (or AMD) CPU has a 12v supply going to it? (Not 0.55v to 1.52v as the Intel datasheet says)
SSD's that have SATA power cables going to them, will have +12v, +5v and +3.3v, but the flash chips will only be using 3.3v or 1.8v.
SSD's that use M.2 only have 3.3v, but the flash chips are no different.
+12v goes nowhere except to more dc-dc converters.
Re GPU's they don't 'use' 12v, everything gpu cards is 1.8v or lower. (possibly a bit of 3.3v too)
If you look at any graphics card, nearly half of the card is a dc-dc psu which takes 12v in and provides the power rails for the ram and gpu chip.
Same goes for the CPU. They don't 'use' 12v. A large part of a mb is another dc-dc psu that provides the regulated power for the chipset and CPU.
I suspect you can run more or less any crappy 12v in there and the psu on the mb will give you a nice clean 1v into the CPU.
I think you are missing my point?
I don't think anything in a PC runs on 12v. I'm not even sure if HDD motors run on 12v? The 12v from the main PC PSU just goes into more dc-dc psu's situated on the mb/graphics card/ssd etc etc.
That's why I don't understand why people look for low ripple in PC PSU's.
Re Dell psu, it's a LiteOn. 375w.
Some good sense there! Thanks.
Well at the moment, no.
If I upgrade to crossfire rx480's and an i7700k OC'd then I think 700w would be marginal and there's no point in running the on the edge of it's specs.
After a good look around, I did find a review on KitGuru of an AeroCool 600W PSU (£30) and it was able to deliver 612W before shutdown. It passed the crossload test and ripple while higher than a mega bucks PSU, was in spec and below the ATX limits, so not an issue either.
I think they marked it down on packaging in the box.
I'd like to see them test the £28 Artic Blue 850W!
Actually I just read a review on the same retailers site, of the 850W Corsair. It costs 5 times more than the cheap 850w PSU but it comes in a velvet bag!
A velvet bag??? WTF?
Reminds me of a CD player I bought once that came with a pair of cotton gloves!
Oh and it was faulty out of the box, so good job it had a 7 year warranty and a nice velvet bag to put it back into...
An AMD Polaris runs at 1.0 to 1.3v not 12v. There is a 12v to 1v psu on the graphics card, that is adjustable.
I don't think anything on a graphics card or pc motherboard runs from 12v or 5v for that matter. It's all 3.3v or a lot less. (maybe an audio amp?). The first thing the 12v on a mb does is goes into a power supply circuit which provides all the lower voltages required by the devices on there.
Likewise the 12v that goes to a graphics board.
The PC PSU is just providing the 'traditional' +12v -12v +5v 3.3V as they have always done. (with 3.3v being a more recent addition) The voltages that the hardware is actually running at has dropped lower and lower with faster clocks and smaller fab processes.
re Arctic Blue. Never heard of them either! but they were on the retailers site I was looking at and are very cheap. 850w for £35 with 4 out of 5 stars and quite a lot of positive reviews. the spec says it has four 12v rails rated at 34A each - which does sound fishy!
Anyway my point was is a £35 psu totally useless and are £150 psu's with unpluggable cables a rip off?
I could always buy one and find out the hard way!
It would be great to see Toms Hardware rip one to bits... or maybe make a market shaking discovery...
Very good link!
Thanks for the replies.
So the ATX standard specifies the regulation requirements?
Regarding regulation, clearly a GPU doesn't run on 12v, that's just the input to its own power control and regulation circuits, so surely having ultra low ripple on the 12v rail is a bit pointless? As long as it's no worse than the GPU power circuit is designed to handle.
Likewise with the mb power circuits. Does any of a mb actually run directly off the the 5v rail any more?
Just trying to understand what's an actual requirement and what is just 'spec-manship' marketing to justify higher prices.
You certainly can't argue with a noisy fan, or worse a fan that suffers a bearing failure, all down to cost of the part.
My old Dell pc has been running fine since 2008 and it has a cheap looking chinese psu in which probably cost Dell $5. (no obvious makers name on the outside unless it's in chinese)
I'll keep on reading!
Anyone know of a technical review of a 'low end' psu compared to a 'high end one? (say Arctic Blue Vs Corsair)
I had a look on tomshardware but couldn't find any cheap psu's!
That's pretty cool!
In these days of added bling & gizmos, I'm amazed more psu's don't have this.
Do any PC PSU's have built in power consumption monitoring?
I'll be looking to make sure I have plenty of capacity for upgrades and overclocking.
Thanks for the info.
I'd tried to reduce my options by just going for Asus and the Asus Strix Z270F was my choice, so glad to see you picked it too. The Asus Prime Z270-A was the other option.
I've seen the 270F for £142, so it's in budget.
Main thing is to allow lots of room for upgrading, more ram, faster cpu and crossfire gpu.
I'll have a good look at the ASRock mb's too.
Thanks for the links, I did think that their results looked a bit off compared to other tests I'd seen.
Just wondered if an extra £10 is worth spending to go for a MSI GeForce GTX 1060 6GT OCV1???
GamersNexus seems to show this card is better than the RX480 cards.
Yes, that's another option. The 8gb model does have a faster memory clock. Not sure if it's much faster because of that.
That's heartening to hear!
I will give it a shot.
It's an old DELL 390 workstation. Not sure if I can use the case as it uses a lot of proprietary fixings and mouldings inside.
Thanks for the advice.
Gaming and VR.
ExtremeTech showed some benefits with 2400, but only 2-4fps.
I guess if 2400 is only £2 more than 2133 it is worth it?
I hadn't considered a 'pentium' cpu, but reading about them, the G4560 seems to be be a bargain.
One set of gaming benchmarks I looked at showed that with a gtx1050ti gpu being the bottleneck, the G4560 was running at the same fps as an i7 6700k.
So there's no benefit of going to faster cpu's without upping the gpu.
thanks for the build! decent gpu in there. I believe the processor has to support SSE4.2 instructions, which I guess all do now?
The slightly annoying thing is that I've had Oculus DK2 running fine on my current machine since 2014, but with the launch of the consumer version last year, Oculus upped the requirements and updated the runtimes such that my pc won't run them anymore, despite not having changed the hardware!
To access the Oculus app store (share) your machine has to pass the spec test and mine fails on the cpu and gpu, despite working fine with the DK2 before - running demos etc.
My old machine is pretty low spec by todays standards, (don't laugh) 1.8ghz intel dual core and a radeon 6850.
So to keep using my DK2, I have to upgrade, so I want to do it at minimum cost but still allow an upgrade path.