Passively cooling i4770k?

I think you will struggle to keep that cool passively at stock speeds, let alone overclocking.

I would go for one of the lower power version like the i5-4570T, which is dual core with hyper threading, so 4 threads. Can turbo to 3.6Ghz, but is only 35w TDP.


Or if you want quad core, then you could try an ivybridge i5-3570T which is quad core, with 45TDP

I honestly wouldn't try it. The best place for that kind of stuff is over at SPCR (Silent PC Review), but even they don't try and passively cool a top of the line fully loaded i7-4770k. Haswell's also run much hotter than Ivy Bridge's and you'd need case cooling to remove all that heat build-up (which defeats the object of a passively cooled CPU). You might get away with doing it on a i5-4570T / i7-4770T (45w) but not an 84w 4770K.

You're better off just going for a low-RPM fan setup (700-800rpm CPU + case fan) which would run at least 30-50c cooler than an all passive (assuming the latter didn't simply crash & start throttling) and in "near silence"...

I have a silence optimised rig - an i5-3570 (non-K or T) OC'd to 4.2GHz with 212 EVO + fans around 700rpm, and a slight -0.1v undervolt (does 4.2GHz @ 1.06v load and 1.6Ghz @ 0.73v idle). It's really quiet even in a quiet room at night with the window closed. Going all passive isn't worth it for performance chips since you've still got case heat-build up to deal with as soon as you load it for more than a few minutes at a time. i3's are the best choice for a genuine need for a totally passive rig (eg, audio recording in an anechoic acoustic chamber).

Well. The rated TDP doesnt tell the whole story.

Intels TDP rating isnt at 100% usage, so in reality if you are working the cpu it can use more power and create more heat than you expect.

A newer quad core might have a lower TDP, and be cooler when not utilized much, but can also use more and make more heat when under load. Thats why I was suggesting the low power versions.

As you can see in the review, the HE02 fails after 9mins continuous load. And even the CR95C shows +62c thermal rise (that's +62c rise above ambient 20-35c case temp, ie, 82-97c load). That's a little too high for comfort. And that's just after 15mins, imagine compressing video for say 6hrs. The problem with Haswell is that under load, the IVR's rather "helpfully" add an extra +0.1v to the CPU when detecting any AVX instructions (which is the last thing you want in a silent PC rig).

If you haven't bought anything yet, I'd suggest an Ivy Bridge i3-3570 (non-K as there's no way you're going to OC on a passive cooler) and then undervolt it as far as your can. On average, you should be able to run the CPU around -0.10 to -0.15v which at stock 3.4GHz should knock off about 10-18w of heat. eg, 77w i5-3570 may in reality run at say 68w. If you undervolt it, you could get that down to 50-58w. If you're really lucky and get a good CPU with a very low VID (stock voltage), and you manage to heavily undervolt it by -0.15v, you could even get it down to below 50w full load. My i3-3570 could run at 3.8GHz (a mild overclock) at just 0.92v with effectively only 40w TDP. Each CPU is different though.

I suggest Ivy Bridge because they do run cooler under load than Haswell's and they don't arbitrarily add +0.1v when they feel like it. They are definitely more "silent PC" friendly in the "voltage is stable under load" sense. Other guaranteed success option of course, is an i3-3240/3250 (3.4-3.5GHz 55w dual core) that could potentially be undervolted down to approaching 30w (from its official 55w).

To be honest though, if you already have one slow sub 700rpm case, fan, you may as well stick one on the CPU because "parallel fan" noise doesn't scale badly at all. Eg, if one 10db fan = 10db, then 2x 10db fans may only = 11db, which is barely imperceptible at typical 1m distance from case on floor, but is worth -30c on a passive cooler. I'm something of a silent pc enthusiast myself and looked at an all passive build but instead settled on an ultra quiet 12-15db 700pm fans instead (cheaper & cooler operation, but still ridiculously quiet). I feel a lot more comfortable with s 55c CPU than a 90c one and there's barely 5db difference.

Edit: There's also BIOS settings to play around with. Eg. the Noiseblocker S1 fan can go as low as 250rpm (that literally is inaudible from 1m away). You could set your BIOS fan control speeds to say 50% (on a 800rpm fan) = around 350rpm from CPU temps 30-70c, then maybe set a "high" speed of 70-75% (700rpm) for 80c, would result in "virtually passive" during normal use, but an extremely quiet active cooling to prevent it overheating under load where +90c temps are a bad idea in general.

Toms did an article on passive/silent gaming pc building here:
http://www.tomshardware.com/reviews/silent-pc-gaming-performance,3435.html

Might be of some use

I see a lot of people here suggesting the 35W TDP i7-4765T and i5-4570T, etc...without understanding that although Intel lists these parts, they are practically impossible to find on the open market at a price remotely competitive with the boxed processors, if you can find them at all. The bottom line is, after doing a lot of research on this topic, I'm come to the conclusion that no passive cooler is going to keep up with an 84W TDP i7-4770K under load, but because it's a K series, it *can* be undervolted and underclocked with a Z87 chipset board to effectively become an i7-4765T.

As of today, an i7-4770K is running $290 USD at Amazon, and there actually is a i5-4570T available from one site for $192 USD, but remember that you are giving up two cores there. I think the i7-4770K underclocked is a much better bet, and then you always have the extra power available if you decide to use it down the road.

In fact, I'm planning on doing exactly that, myself. I'm looking at the Gigabyte Z87MX-D3H microATX board, to have the option of two PCIe v3.0 x8 cards directly into the CPU at a manageable price. Pop in 8GB of Kingston HyperX LoVo DDR3L-1600 RAM, top it with a Cooler Master TPC812 sans the fan, power it with a Seasonic fanless, and underclock/undervolt the whole rig. With an SSD and no case fans, it should be perfectly silent, save for power supply whine, if any, and no moving parts, at all.

Why? Because I want a totally silent PC that isn't going to limit me down the road, especially if the whole experiment fails. I'll still have a fast processor, a good motherboard, an excellent cooler, and a fantastic power supply, etc, etc, so if I want to crank up the juice and clock, I don't have to buy all new parts.

The only real question I have is the GPU. the HD 4600 is fine for web browsing, but if I want to play a game, even though I'm not a huge gamer, I need to wrap my head around passive cooling one or two Radeon HD 7750's in this puppy without disrupting the convection too much, or overheating something.

But again, even if passive cooling turns out to just not work, then all I have to do is add a couple of fans, and I'm no worse off than if I'd never tried the experiment, at all.

http://www.hd-plex.com/hdplex-h10-series/ supports CPU up to 125W. What about that?