Is a 300W PSU enough for a i5 4690k and a GTX 960?

CountDown · Feb 19, 2015

Hi guys, I am going to build a new pc soon, and I am thinking of using a mini-ITX case (Silverstone Raven RVZ01) that requires a SFX PSU. I had decided to buy an i5 4690k (which I do not intend to overclock, at least not yet; on the contrary, I might downclock it if it is too hot/power hungry) and a Geforce GTX 750 Ti, along with 16 GB of RAM and a SSD 850 Pro. I thought a Silverstone ST30SF SFX 300W might be ok, but then the GTX 960 came out, and damn, I am really tempted! It's still very efficient, cool and quiet while being a lot faster, and in general it would be better. The point is: can I run all of this with such a small PSU that can only provide 300W, and only 22A on the 12V lane, which means 262W?

I am really unsure. PSU calculators online don't seem to know the GTX 960 yet (for example http://www.extreme.outervision.com/psucalculatorlite.jsp), and anyway I don't trust them too much, as I read really odd results in the past. I am trying to gather data from reviews, to figure out how much power such a system would draw. Here's what I've concluded:

First of all, Nvidia recommends 400W. And guru3d agrees. But...

I have found some reviews in which they use systems similar to mine (though normally they have an i7, and even overclocked to ensure the CPU isn't a bottleneck for the GPU which is being reviewed), and the power consumption at the wall is around 200W. At the wall, considering a loss of 10% means that the system draws around 180W. This would be 60% of my PSU's capacity, and around 70% of the 262W that can be provided by the 12V lane. This isn't too high, especially because I won't be playing games all the time - no more than 3 hours a week, probably.

Here are the reviews:
-hwupgrade.it has tested the MSI GTX 960 Gaming 2G and the Inno3D iChill GTX 960 models. They used a 4790K@stock, 16 GB RAM, and an Intel SSD 520 240 GB, and their highest reading is of 212W (at the wall) for the Inno3d card running Metro Last Light; the highest for the MSI card is 203W. Since this is at the wall, it means the system absorbs at most 90% of it (assuming the PSU can reach an efficiency of 90%, which is not so easy at a load of 18% for a 1200W, gold-certified PSU), that is, not more than 190W and 182W.
-Guru3d, already mentioned earlier, uses an i7 3960x@4.6 GHz. They say their test only stresses the GPU, but their CPU is such a monster that the system idles at 120W. And the total consumption, with the GPU at 100%, is of 237W.
-Tom's hardware has done a lot of in-depth testings. Unfortunately they haven't tested the MSI card I am aiming for, but of all the reviewed cards they have found the highest consumption while gaming to be below 110W. And apart from the Asus card, which has some nasty spikes that take the total system consumption well beyond 300W, all the other cards barely reach 200W.
-PcPer has tested the Asus card. They found that while playing Metro Last Light the card rarely even reached 100W, for a total of 228W using an i7 3960x with 16 GB of RAM, and with Dota 2 it stays around 33W (!!!).
-Techspot has tested the Gainward GTX 960 Phantom. The total system consumption in the worst case (Metro Last Light) is of 209W, using a Intel Core i7-4770K (3.50GHz), 8 GB of RAM and a 512 GB Samsung SSD 850 Pro. The PSU is a OCZ ZX Series 1250 W and its efficiency is around 90%.
-hardocp has tested the MSI gaming card, and at full load the system consumes 244W. The system is very power hungry: i7 3770k@4,8GHz and 16 GB of RAM, using a 1350W PSU.
-kitguru uses a 4790k (stock? No idea, but probably yes), 16 GB of RAM, and gets 197W with a Gigabyte GTX960 G1 Gaming SOC.
-If Anandtech got around to publishing that review, I'd be happy to check their results, but despite yesterday Ryan said he is "working on it as we speak", all is quiet.

Everything I have gathered so far makes me think that the ST30SF is adequate. But why does everybody recommend 400W or more? Is it just because until some years ago these low numbers were unconceivable, and people are still sticking to old numbers and safety margins? Or is it because they are taking into account things I haven't calculated, like capacitor aging, some spikes (like those shown by Tom's Hardware) and so on?

In other words: do you think I could go ahead and do it? Or should I rather step back to my original choice (750 Ti), or upgrade the PSU to the ST45SF model (either bronze or gold) which provides 450W? In the latter case I would be using 40% of its capacity, wouldn't it be overkill?

shilka · Feb 19, 2015

The correct way to use the extreme outervision PSU calculator

CountDown · Feb 19, 2015

Hi shilka, thanks for the hint, but this doesn't solve the problem that the GTX 960 is not in the list. The latest update to the site was on September 16, 2014.

shilka · Feb 19, 2015

I dont think 300 watts is going to be enough for a GTX 960 you are going to upgrade the PSU.

epic1337 · Feb 22, 2015

the reference 960 will only pull 100watts average.

your rig will work on a 300W PSU but you'd be bordering the limit, i suggest going with a 400W PSU minimum.

Cyro999 · Feb 22, 2015

good 300w psu is fine.

You can make a 960 consume ~75-120w or so, depending on clocks. Adding that last 20% performance uses like 1.6x more power because of voltage scaling, it's pretty nasty but they're amazingly efficient around 1200mhz.

Since it's only 262w, i wouldn't get it if hoping to OC both CPU and GPU. For stock clocks though, even that's plenty.. though i didn't google for PSU reviews. Don't trust guru3d, nvidia or a PSU calculator. The first 2 post hugely overinflated numbers sometimes (like 850w for 970 sli) and the third one relies on you inputting very accurate numbers for part power consumption (which you wouldn't need to use the calculator if you knew that in the first place) and using them in specific correct ways

CravinR1 · Feb 22, 2015

If you only pull 300 watt you dont want your psu at 100% load.

300 / .8 = 375 minimum for 24/7 use

Cyro999 · Feb 22, 2015

If you build so that 100% load is a fair amount under combined CPU + GPU 100% load at maximum clocks, they won't be there most of the time.

I can pull ~400-450w but my actual load during games is usually around two thirds that

latelesley · Feb 22, 2015

http://www.techarp.com/article/Desktop_GPU_Comparison/nvidia_f8x2jdj2784h2mk9xegskdhq234o2_4_big.png

the 960 is listed as 120W on here. that'll leave about 140W for the 12V of other components. CPU is 88W TDP - so it may draw up to 100W-120W (fully loaded of course, real world will be nearer the 88W mark), that leaves you 20W-40W for other components. You've no HDD, SSD will run on 5V probably, fans and the motherboard are the only other consideration, fans could be about 4W-6W each, motherboard it's hard to tell, as it'll use the 5V and 3.3V for powering a few things, so the only real 12V draw will be the CPU, and some minor stuff.

It's tight, but I think you'd get away with it. But as @Cryo999 said, I wouldn't overclock.

This is all assuming it's a decent PSU, continuous rated, and not a cheap peak rated PSU.

Jeebus87 · Feb 22, 2015

I think that's a big risk. Unless if you are rich and wont mind if motherboard, gpu, cpu, ram all die when powersupply fails. Then go for the 300W

If a PSU does not fit then stick it outside or ghetto rig it. You know I had to ghetto rig a 450W supply for my Sony Vaio desktop, the OEM case can't fit it so only half goes in and rest is hanging outside with some aluminum tape!

What is the dimensions of this case? I bumped into some 350W PSU awhile ago when searching for a matx one. So maybe look for a 350W PSU instead.

latelesley · Feb 22, 2015

Quote:

Originally Posted by Jeebus87

I think that's a big risk. Unless if you are rich and wont mind if motherboard, gpu, cpu, ram all die when powersupply fails. Then go for the 300W

If a PSU does not fit then stick it outside or ghetto rig it. You know I had to ghetto rig a 450W supply for my Sony Vaio desktop, the OEM case can't fit it so only half goes in and rest is hanging outside with some aluminum tape!

What is the dimensions of this case? I bumped into some 350W PSU awhile ago when searching for a matx one. So maybe look for a 350W PSU instead.

Well, my system had a PSU die a while back, (a silverstone 1200W), and I got a seasonic G-360W running it just now. I've an athlon ii 440 unlocked and overclocked to 3.6, and have a 750 Ti card, 8Gb RAM, 1 SSD, 4x HDD's, 2 fans, and the most i've had it pull from the wall under stress test, is 325W. taking the supply as 90% efficient, that means my system drew 293W roughly. 300W will cover it, IF it's a decent PSU. many PSU's can run over their rating for short periods, and it's not as if it's going to run full stress 24/7. Gaming will probably pull the most, but still not as much as full stress.

Cyro999 · Feb 23, 2015

Quote:

CPU is 88W TDP - so it may draw up to 100W-120W (fully loaded of course, real world will be nearer the 88W mark)

Actual usage for those CPU's is really in the ~60w range, not 100-120w.

There's a few reasons for "tdp" being that high;

1; TDP does not mean power consumption, it's long duration package power limit

2; that includes the igpu, it's basically the power window that the cpu + igpu will use turbo boost around. If that window is hit, turbo boost frequencies will be reduced back towards guaranteed frequencies.

3; It's conservative

4; Intel kept the same number on i7 as i5 even though i7 uses like 15% more power in many cpu only workloads, simply to make the i7 look better

960 will only use 120w if it's using highish voltages, like ~1.2 - 1.25v. Like i said above, getting that last +20% performance from overclock makes it pull ~1.6x more power just because of the big voltage change

DrBrogbo · Feb 23, 2015

Yes, if you don't overclock, you could run every component of that system at 100% load and safely stay under 300W. I have a QX9650 (130W cpu) and a gtx 980, and when I'm stress testing with prime95 and Unigine, I'm barely pulling 350W from the wall. That means only 320ish watts going to my system.

The only problem is that there aren't too many quality 300W power supplies out there. If you can get a high-quality 300, you will be fine. However, I would probably grab a decent 430W and have room later to overclock.

toyz72 · Feb 23, 2015

i've been researching this case for about 3 days now. i think the 450 would be the best route. the case only accepts sff psu's. the 450 would leave you lots of head room if you go bigger later on. this is one of the harder itx cases to work with.....so i'd get it right from the beginning and save myself some headache,haha.

CountDown · Feb 24, 2015

Thanks for all the replies, and sorry for not showing up for so long (but I'm reading the email notifications every day, though I have just discovered I got only some of the posts, not all of them, so I'd better come here and read directly instead of checking my mail).

As far as overclocking is concerned, it is certainly not my intention. Not for the GPU (the factory overclock is more than enough, and I might actually bring it back to stock if I feel it's better for temps and consumption), and for the moment not even the CPU. Overclocking the CPU is something that I consider for years to come, as a replacement for buying a new CPU: after all, each generation has a 5-10% increase over the previous one, so I think that by choosing a high-level one (it "only" has 4 cores, but on the other hand it's the fastest 4 core on the market), which is probably overkill for now, and by gradually increasing the clock I could keep this CPU for many years. But in the meanwhile there's no need. Actually, the reason I want a 4690k is that the price difference for a Z97 motherboard and the K CPU, compared with normal ones, is quite small (with respect to the total system cost), and the k version gives me the ability to downclock as well. My initial pick for a CPU was the 4690s, hoping this would help containing temperatures and consumptions; I have ditched this option simply because the few reviews I have been able to find have shown little to no real benefit. Instead, I prefer to be able to set the clock manually. I could even replicate the 4690s Turbo Boost configuration (3.9 GHz with 1 core, 3.8 GHz with 2, 3,6 GHz with 3, 3,5 GHz with 4) if I wanted to. Which by the way isn't too far from the stock frequencies of the 4690k (3.9, 3.9, 3.8, 3.7). Source: Wikipedia.

And as far as the dimensions of the case are concerned, it's very small: 382mm (W) x 105mm (H) x 350mm (D), 14 liters, similar to an Xbox 360. The PSU must be SFX, there's no way around it.

But I have to say I was only considering Silverstone PSUs, and I wouldn't be too happy to switch to the 2 450W models, because the bronze one doesn't have such high quality as far as I read, and the gold one is reported to be very loud by a lot of users. The first generation was apparently very bad, then they released a new model but chances are still high you get one which is unpleasantly loud. I am not a silence freak, but really too many people are unhappy with it. But now, following this site's guide, I have also noticed the PSUs made by BeQuiet. They haven't been reviewed by Jonnyguru and they rarely show up on pcpartpicker, which is the main reason I hadn't taken them into account, but it looks like they are good - after all, they are recommended by this site, so they can't be bad. And the good news is they have a 400W PSU! Maybe its quality won't blow me off my feet, but after all 80+ bronze and non modular is the same as the ST30SF that I was considering. I'd have to give up the semi-fanless design (which according to some is actually a good thing, as it is dangerous to have a fan that stands still because it could lead to pockets of hot air), but in return I would get 100 more watts. I think I'd still prefer the Silverstone overall, but if the margin is too tight I think I can switch. I'll investigate a little more.
@toyz72: if you check the RVZ01 owner's club you'll discover that only the ST45SF-G fits the case perfectly, as the holes in the case to let the air out are in an unusual position, which means that with any other PSU they are partially occluded. I wouldn't have many problems drilling some new holes in the case, but you might not like it. In that case I would say the ST45SF-G is the only option.

For the moment, thanks a lot to all of you, especially for having the patience to read my posts, which aren't really what I'd call short and concise (and you haven't seen the full description of my pc yet - just give me the time to finish it and I'll post it, and then good luck reading it, it's already over 25K now...)

davdav · Aug 13, 2016

Hey
awesome research work on the first post thanks it helped me a lot.

I added a gtx 960 on 300W ( check my "rigbuilder" )

I downcloked my I5 4590 to around 5% in the power supply option of windows . It brings the cpu down to 3ghz. It prevents it from going in turbo mode.
Turbo consumes almost twice the energy
( energy monitored via cpuid only )

I unplugged my DVD rom ( just pulled the cables, no worries )

A bought a gtx 960 4G but with a bandwiith of 125 bits ( NVIDIA )t. It consumes 120W isntead of 150W for a bandwith of 190 ich bits.
But it's creates a bottleneck on the GPU.
The GPU can utilize maximum 3.5G but the information must not go to fast ( big explosions )
Fall out 4 there is one ambiant occlusion mode that I can not turn on or lag
Star Wars battlefront Super SAmpling mode creates lag
I play in 1080p

So yeah you can make it happen with 300W but if you can get 400W go for 400W

Is a 300W PSU enough for a i5 4690k and a GTX 960?

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epic1337

Cyro999

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Cyro999

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