Silent PC

Top view

Top view

Fanless PC case by Original Twist

A totally silent Mini ITX PC case made from low-cost, off the shelf components with easy progression from prototype to large scale production.

Things are moving on in the world of desktop computers; they should be cheaper and simpler, but, would you believe it, they’re not. Why?

Main CPUs run much cooler and use less power so, unless you need a powerful gaming rig, you don’t need big fan cooled power supplies or case fans. Heat pipes can remove all the heat a CPU  makes.

Solid state discs (SSDs) are cheap and built into motherboards. Hard drives are not required at all when data is stored in the cloud.

Delete the SSD and HDD parts on the drawing and what is left? Just a mini -ITX motherboard and an open power supply; two components then.  No moving parts, no noise and surely less cost.

The Original Twist fanless PC case

The extruded fin case side is glued onto extruded aluminium corner sections; both are available from stock.  The corner sections have slots to accept side panels in any material – the blue parts on this drawing could be marble, for example, or wood.

The huge finned extrusion makes one side of the case.  By huge, I mean really huge. 40mm deep and 160mm wide with a 10mm thick base all ready for embedding 6mm heat pipes. Heat transfer is via 6 heat pipes.

There are multiple disc drive mounting options opposite the motherboard and also higher up the case if they are required. An SSD would, these days, be incorporated with the motherboard but it can easily be fitted above if required.

The open case power supply (PSU) is mounted low down in the side channel extrusion.  Any heat produced from this and the motherboard drives the updraft.  There are no other components and no moving components at all.


Side view

Side view

The Magic Power (PSU), that fits the case, is 80W so that much heat needs to be handled by the case.  Any more power will need a Pico-PSU i.e. an external brick with internal ATX distribution leads. The case can cool up to 100W but most CPU chips will run well under that level. The 6 heat pipes only use the top half of the case but extra heat pipes can be fitted down the side to bring the bottom of the big heat sink into play.

When standing up the tall chimney case draws air up through the bottom and expels it at the top so cooling is effected both inside and outside the case. The aluminium corner extrusions are part of the heat sink and are bonded on with heat transfer glue.

The finned heat pipe clamp on the CPU sits neatly in the airflow (splayed fins would be better) as do the heat pipes on their path to the side wall. The mother board, mounted at the bottom of the case, heats the air at the lowest point. Full height cock’s-comb RAM coolers also heat the air low down.

The heat pipes go across then down to the sink so the motherboard becomes upside-down when the PC is on its side with the heat sink uppermost.


Case size 124.5 x 240 x 350mm

The components dictate the shape.

Width – the I/O shield between 2 corners

40+44.5+40 = 124.5mm.

Side length – the finned extrusion between 2 corners

= 160+40+40= 240mm

Height/length – 170mm motherboard with HDD above – 350mm.

While it is big enough to house that monster cooling extrusion it is not as tall or deep as a typical small form factor PC and only slightly fatter.


Design notes

The corner extrusions come with threaded inserts for the ends and these are used to bolt on the top and bottom plates.

4 big round feet enable the start button to be fitted in the base plate as well as the ‘power on’ LED and an angled power plug.

The radiused corners on the end plates match the case style.


Market position

Various Zotacs and the Compulabs Intense exemplify this silent PC slot but they are too expensive and none have enough cooling power for fast processors.

The Hdplex and Streacom cases both employ similar heat pipe cooling but with less cooling power and more complexity.

The Original Twist Fanless PC case will deliver higher performance for a much lower price.

The beautiful, contrasting black and aluminium finish looks truly modern making this ‘the computer you want’ and in every way better than ‘the computer you need’.  Design flexibility allows the non cooling sides to be in various materials such as wood, aluminium or marble, none of which requires special tooling to produce.


This case provides excellent flexibility for product variation and expansion. The side panel with the I/O plate is long enough to mount DVD players or removable drive bays.

Marketing words?

Our philosophy is simple. Cut waste and spend the difference on better components.

Designed in solid aluminium this PC brings you beautiful modern looks that reflect the quality and performance of the internals.

To bring you the best value for money with absolute reliability we removed all the moving parts. All discs and fans have been replaced by top quality components to bring you the best value, high performance, totally silent PC.

The Gigabyte motherboard is sheer indulgence – top quality with built in Wi-fi and built to last. It is WiDi compatible too so a wireless link to your TV is easy.

The 120 GB solid state drive gives exceptionally fast boot times and application loading.

Super fast USB-3 ports are available for you to plug in your external media storage devices or there is room inside for a hard drive with support for up to 3Tb.

The side plate holding the PSU can also house an optical media drive bay (41x146x185mm- dotted line on the drawing). A blue ray player built into your ‘Original Twist i3’ makes the perfect HTPC.

The Technical stuff  below … read on if that’s your thing


heat pipe layoutThe computer is assembled with the finned side down. The heat pipes are cranked down once clear of the motherboard and are pressed into the machined slots in the side. After that the PSU channel and the opposite face plate are fitted along with the I/O plate.

Any SSDs or HDD are screwed onto the lid with their looms running neatly up the side so as not to impede airflow. This lid and attached corners then bolts on and finally the end plates hold it all together.

The bending of the heat pipes is fairly minimal but it is, none the less, quite critical. The sketch above shows how just 3 shapes of bend are needed to fit all six pipes. The yellow positions show where additional heat pipes could be laid to increase the effective case length. The pitch of the heat pipe slots on the heat sink have to be exact multiples of the pitch on the CPU block.

Thermal performance calculations

The 6 heat pipes on the CPU block can remove at least 15W each and almost double that with the case in the upright position. Additional air flow through the case in this position will also remove some 10W from the CPU heat sink. So the removal side is good for over 100W but, of course, we need to dispose of this heat through the case.

The heat pipes only lie in half of the finned side and the manufacturer’s figures suggest a DegC/W of 0.45 for this length. With the CPU at 50C and a room at 22C we would be looking at 62W cooling power which would comfortably cool the Intel Core i3 chips. Actually CPUs can run much hotter and the cooling power would be equally higher.

The heavy aluminium heat sink side has plenty of room for five additional heat pipes to be placed between the existing ones and with heat pipes embedded along its entire length the case would be able to remove around at least 80W.  It is hoped that the case will be able to lie flat for 55W chips and be good for practically anything while standing up or on a VESA mount. The added cooling power of the corner extrusions has not been taken into account in these calculations so real world performance should be much better than indicated.

Theory is all very well but we can be sure by comparing with several existing silent PCs which work perfectly well. The Original Twist design has cooling surfaces of around 5 times that of the others so this should be the best of its kind. Some PCs have heat sinks; this PC is a heat sink!



This case is not in production yet. If you would like to own this design and the business of producing it please use the Original Twist contact form.


Awesome PC and touchscreen in a desk design

DeskPC sideDeskPC topDesPC deskThe Original Twist PC in a desk
You may be an architect or graphic designer or you might just want a flash looking office; either way here is a computer and desk idea for your viewing pleasure.
Windows 8.1 is the steering influence for the desk. Swiping and pinching at the screen is all very fine but reaching forward is not very convenient and greasy fingerprints are the last thing you want on your high resolution monitor. The answer is to have 2 screens; a touch screen set into the top of the desk and a separate monitor standing up in the usual place. A crisp white desk with inset monitor will make your studio look pretty smart but we can add extra technomologicalness with a glass panel set into the desktop to show off the high spec PC components built in underneath. If you could even source a desk like this it would cost £thousands so this project is about making one for yourself. The desk-top part is quite easy to make in MDF and a durable finish can be achieved with polished Hammerite paint. A pair of ready made office drawer units, painted to match, make suitable supports for the top.
So onto the computer case made in 18mm and 12mm MDF, some Perspex all completed with a glass top. The sketches here show how it goes together. Note in particular the false floor which hides most of the wires and how the motherboard is raised slightly to give better airflow around it. The curved section is made from a stack of MDF parts cut with a jig saw and capped with a small Perspex support for the SSD. The finished case will be bolted up under the desk and capped with the glass top set into the desk.
To flesh it out more we’ll go through the components that would make a top of the range designers PC and then we’ll add up the prices using the fabulous web site.

Corsair H100i CPU cooler.
The whole design rests on this pre-assembled water cooler which will cool the CPU while its fans draw air across all the other components. It comprises of a pump block to go on the main processor chip with a pair of pipes connecting a large radiator with 2 fans on it. The exhausting air flow is choked across the narrowed section of the case containing the motherboard and the hard disk drive. The fans are controlled on the Corsair Link and will run almost silently unless heavy CPU loads are imposed when the full 77cfm flow comes into force.

Mini-ITX motherboard
Asus Z87i–pro. Successor to the Z87i–deluxe this is a top quality and great looking board. The Wi-FiGO feature enables rapid start up with a swipe of a dongle or even your phone.

Intel 4770K Core i7 Haswell processor.
Without going into mega expensive speciality chips this is about as good as it gets. The H100i is well up to cooling this latest generation Haswell CPU even when overclocked and the cooling limits are actually related to heat flow across the chip rather than the water cooler itself.

RAM Corsair Vengeance Pro 2x8Gb DDR3-2400
16Gb is as much as the motherboard will support and that is enough for most users. Not only are Vengeance Pro top quality memory strips but they add some shiny bling to the board. Note that we have moved on from DDR3–1600 which is not fast enough to match Haswell CPUs.

Asus GeForce GT610 low profile graphics card.
Full sized cards are too big for the case as shown but this little fanless card might be good for some undemanding applications. The on board graphics of the Core i7 chip are pretty good of course so some systems will be perfectly fine without a graphics card and there is no particular need for one to drive the 2 screens.

Samsung 840 pro SSD
This 260Gb solid state memory is currently hugely popular and will ensure super fast boot up times and application loading.

Hard Disc Drive – 3.5”
This rather boring component looks great with passive coolers and sound damping rubber suspension fitted into a 5.25” drive bay bracket. A couple of Akasa aluminium finned side mounts will look and perform well without significantly impeding airflow.

Corsair Professional Series AX 760i Watt Digital ATX/EPS Fully Modular 80 PLUS Platinum Power Supply Unit.
760 Watts is greatly in excess of requirements but the bonus is that on light loads the inbuilt fan won’t even run at all. Like the H100i cooler the parameters can be viewed and controlled by Corsair Link on the PC. Quality is matched by the 7 year guarantee. The unit is modular so only the cables needed are used and being black and flat they will fit under the false floor and pretty much disappear in the case if it is painted black.
Note that the PSU is mounted on its side outside the case in a corner cut out; an arrangement that isolates the cooling from anything else going on in the case. The width of the unit determines the 150mm height of the PC case before the glass goes on top.

How much?
The PC parts come to almost exactly £1,000 which is remarkably reasonable for such a high specification. As only £400 would be saved by downgrading all the components to something more ordinary most professionals would just go for the best in the interests of reliability and performance headroom. The 2 screens will add at least £500 so in total the whole project could come to about £2,000 which is fantastic value for something that will make your offices look ultra modern. It goes without saying that productivity will be maximised with such a useful workstation.

N.B. The design was done by dragging appropriately sized boxes around in Excel. If you want to use or modify these designs just message me and I’ll e-mail the file to you.
Also please note: The cooling of components may be very much on the excessive side but even so this is all untried and should be treated as a suggestion and starting point for someone who is computer savvy.