
Common sense dictates that submerging your high-end PC in cooking oil is not a good idea. But, of course, engineering feats and science breakthroughs were made possible by those who dared to explore the realms of the non-conventional. Members of the Munich-based THG lab are only too happy to confirm this fact. And not only did we find that our AMD Athlon FX-55 and GeForce 6800 Ultra equipped system didn't short out when we filled the sealed shut PC case with cooking oil - but the non-conductive properties of the liquid coupled created a totally cool and quiet high-end PC, devoid of the noise pollution of fans. The PC case - or should we say tank - also offered a new and novel way to display and show off your PC components.

Remember our Record Attempt: The 5 GHz Project when we went to cooling extremes with liquid nitrogen, Build Your Own XGA Projector! or the PC that manages with just 37 Watts of power? And don't forget the Espresso machine in the PC case. And now? Many hours of work along with preparation time coupled with numerous glitches are behind our new one-of-a-kind specimen.

Initial attempts with oil in a plastic container.
Technically, our attractive high-end PC can keep up with the best of the crop as far as performance goes - minus the noise, of course, associated with an extremely loud standard 08/15 case. Indeed, the large volume of liquid guarantees absolutely silent operation - no fans are running. And even under maximum load the three major building blocks remain sufficiently cool: processor, graphics card and chipset.

The Do-It-Yourself Oil PC: Pour eight gallons of vegetable oil into the running benchmark operation and the silent Athlon-FX-55 system is ready. A GeForce 6800 Ultra as well as other components are included.
Our video 18 follows a completely new approach to the cooling of a high-end PC system: eight gallons of oil are poured here into a specially prepared case with powerful components. And all that during benchmark operation!
The videos from the Munich-based THG lab have been followed by a wide audience ever since the first film in 2001. As we did for our previous films, we offered Video 18 in three different formats from the get-go. All the while, we've always attempted to achieve an optimum picture quality with a comparably very low bit rate.
In order to cater to the wishes of a few readers who don't want to install an additional video codec, we offer the new video in WMV9 format for the MS Windows Media Player as well as for Apple in Quicktime format (H.264).

Apple has caught up with its Quicktime format (7.0.3 Pro), which is much easier to operate than the competition. The video was coded with H.264.
In addition, the file is compressed with a ZIP packer so that, as a result, a 20 MB file is ready to be downloaded. A playing length of three minutes and 45 seconds with stereo sound results in an average bit rate of 5.7 MB/min, or 93 kB/s.
Our preference for the DivX codec has changed, since the new version 6 is less suitable for encoding than its predecessor 5.2.1. Thus, for this video the "old" version was again used for now. The market for compressing procedures is transforming altogether in that the Microsoft WMV9 codec is displaying good characteristics similar to the DivX 5.2.1 and is much easier to handle. Apple's Quicktime Pro 7.0.3 has also really caught up and now works with the modern H.264 codec. The handling is the easiest thing in the world and clearly better than for DivX or WMV9. You can convince yourself by simply downloading the Apple version of the video.
The new video can be downloaded here:
Download video 18 in the DivX format
Download video 18 in the WMV9 format
Download video 18 in the Quicktime format
If the video doesn't play, then you can download and install either DivX Player, MS Windows Media Player or Apple Quicktime Player.
| Technical data THG video Oil PC | |
|---|---|
| Video resolution | 540 x 432 @ 25 fps |
| Aspect ratio | 4:3 |
| Color depth | 16 bit |
| Audio signal | Stereo, 16 bit, 48 KHz |
| Bit rate audio | 96 kBit/s (12 kBytes/s) |
| Bit rate video | 650 kBit/s (81 kBytes/s) |
| Total bit rate | 746 kBit/s (93 kBytes/s) |
| Compression video | MPEG-4 DivX, 5.2.1 Pro codec, 2 pass, bi-directional encoding |
| Compression audio | MPEG-1 Layer 3 (MP3), Fraunhofer |
| Color space | YUV |
| Run time | 3:45 minutes |
| File size | 20 MB |
Our shopping list for the Munich computer mile is not particularly long: An AMD Athlon 64 FX-55 available for $1,079 as the processor - a GeForce 6800 Ultra PCIe graphics card costs $359. Among further components are a motherboard from Gigabyte K8NXP-SLI with an NForce-4-SLI chipset that costs just under $220 as well as DDR400 memory (1 GB) for $120, and an IDE hard drive from Maxtor with 320 GB capacity for the reasonable price of $155. We still have little things like a keyboard, mouse or 16-speed DVD burner available. In total that makes just around $2,000. At this point maybe a comparison is helpful: The typical Aldi PC including useless accessories goes for around $1,200.
Trials With Distilled Water
The idea of building a liquid-cooled PC is not new. Back when tuning and overclocking topics were still in good taste, we thought about applying "massive" cooling concepts. But back then water cooling emerged, which initially squelched these thoughts. Shortly before Christmas we took up this topic again and undertook initial trials with distilled (de-ionized) water. Water as a medium has the advantage that, when the case is completely full, it still allows the components to be highly visible as a result of its transparency. And it offers a better thermal conductivity than oil. This is necessary above all when high-performance chips such as the Athlon FX-55 or a GeForce 6800 Ultra are being used.

After five minutes a short circuit occurred with de-ionized water.
The hardware was placed in a container in which five gallons of de-ionized water were poured. To everybody's amazement, the system ran solidly for a period of five minutes before crashing. We repeated the assembly numerous times after the hardware was dried. The expensive components had suffered no damage. Accordingly, this solution was deemed unviable.

Initial tests of the
Athlon FX-55 system were conducted in a plastic tray. In the picture you can also see a Zalman cooler; it was no longer used this way in the final system. After the failures with distilled water, we quickly switched to oil.
After the failed trial runs with de-ionized water, we quickly switched to oil. In contrast to water, this liquid has the crucial advantage that far fewer free ions (dangerous leak currents) are present. In the trials with water it had been determined that in the case of local shorts the components did not suffer any permanent damage. In the final analysis, the danger of losing $2,000 worth of hardware within a few minutes was thus averted.

Temperature readings at major points of the platform in the oil bath.
A compelling prerequisite for stable operation is the use of a heat sink - required equally for the processor, graphics chip and the chipset. A heat sink was used for the AMD Athlon FX-55 that only had its cooling fan removed and thus worked passively. The Zalman cooler shown in the pictures was no longer used later in the final Plexiglas case. As for the GeForce 6800 Ultra graphics card, only the metallic heat sink remained. The chipset ventilator from Gigabyte K8NXP-SLI did not exactly promise great results and thus was disconnected; after all, the fan's blades are not designed for low RPMs that result from high friction resistance in the liquid.
The temperature readings at the important points proved that the oil liquid was sufficient to cool the chips passively in continuous operation. And so we were able to find a suitable case.

Reading of the temperature on the Zalman cooler by means of metal feelers.
After stable operation has been secured, the following items are necessary: special glue, silicone, tools and last but not least a sufficient quantity of vegetable oil.

Pluggable bits are helpful for tight spaces.

Knife to remove burrs.

Plexiglas to seal openings.

Nothing works without silicone to seal off the side walls.

The eight gallons of oil.

We struck gold by finding a transparent case to show off our DIY oil PC masterwork.
The underlying thought behind this project was to design a system that cooled the components by total submersion in a liquid-filled case. The lab engineers immediately set two conditions: The system should run silently and only choice hardware should be used. We also sought out an attractive container or case. Using an aquarium was excluded from the very beginning - cables and connections couldn't be cleanly brought from the inside to the outside. The system had to look good, too. In the end, we decided on a transparent PC case made of Plexiglas, which however meant an immense labor expense. All contact surfaces of the individual edges had to be glued and made airtight. The sealing of boreholes and openings on the individual slabs meant additional effort. Step by step, first special glue and then silicone were used. The latter particularly needs time to cure, making the use of a dryer recommended.

All screw joints in the case have to be loosened, followed by wetting with special glue.

To seal the openings, we got Plexiglas slabs that we cut accordingly. If you expect the oil smell to be a problem, then you should plan for a top cover right away. However, the heat exchange between the oil liquid and the environment will then be altered.

All parts of the case must have airtight contacts.

Glue with a dosage tube.

An electric keyhole saw proved necessary to working with the Plexiglas slabs.

All corners and edges are made impermeable with silicone.

The graphics card slot becomes impermeable with the help of a VGA/DVI adapter.

Afterwards, sufficient silicone is deposited - in the final solution we then also added a Plexiglas strip.


The CPU base must be sealed tight against seeping oil - otherwise there will be problems. To achieve this, the retention module is glued to the heat sink and the motherboard and then additionally made impermeable with silicone. However, this can easily be removed in case you want to change the CPU.
Our initial attempts had shown that the poured oil sporadically led to crashes. The cause was also quickly found: The processor base together with the CPU and the heat sink had to be made impermeable to the liquid. Quite a bit of labor and time are necessary for this, since just like for the case, we first had to use special glue and then silicone. After successful sealing, the system works without a hitch.

We have the following explanation for this phenomenon: On the motherboard in the area of the CPU base, the oil is responsible for increasing the capacitive resistance between the individual wiring. In short, the oil acts as a dielectric material. Since very high frequencies occur on the motherboard, the capacitive resistance goes down. Accordingly, this then influences (or tampers with) the digital signals, particularly in the area of the CPU base. After all, 939 pins are located there in a very tight space.

Inserting the motherboard on a trial basis with PCIe graphics card and placing the ventilators for an initial check. Later the motherboard has to be removed again and the processor sealed.

Here a pluggable slot ventilator can still be seen in the picture, which then ceased to function during operation. In the end it was not used.

View from the bottom of the case all glued - here you can see the slot ventilator described. A short time later it gave up the ghost.

Rubber stoppers in the bottom of the case to let out the oil if needed.

The PC system is already running with passive cooling - now the oil has to be quickly poured in.

As soon as the case is absolutely tight, in principle the pouring of the oil can begin. The fact that the system was started first with only passive cooling made us nervous. Therefore, we wanted to fill the thing up with oil without delay; otherwise, you run the risk of the processor or the graphics chip overheating, of course. By contrast, the variation of first filling the oil and then starting the computer is less dangerous.

It is finished: 8 gallons of vegetable oil have been poured into the case - the system gleams through silent continuous operation.

This is what it looks like when everything is tightly sealed.

View from the side into the case.
During the entire testing, the PC - filled to the brim with oil - in the transparent case was an absolute eye-catcher. Silently it performed its work - very slowly the oil got warmer, eventually reaching just under 104 degrees Fahrenheit (40c). Above all, it was not noticeable that the system was running under maximum load.

Before dismantling the motherboard, the oil has to be drained.
Originally it was planned to equip the oil PC with an Athlon FX-60, but this processor had not been officially introduced yet by AMD. Thus, the AMD Athlon FX-55 (2.6 GHz, 1 MB Cache) together with the Socket-939 motherboard base and the GeForce 6800 Ultra were used. And so the system is still faster than a comparable PC with an Intel Pentium D 840. Our DIY system with its higher performing hardware costs just under $2,000 and works absolutely silently. The passive cooling of the eight gallons of oil in the case see to that. In order to get this result, a few steps are necessary that are shown in the video and accompanying pictures and text. Our prototype of an oil PC should just be a starting point. Slowly rotating ventilators can surely be installed to optimize the thermal convection within the liquid, for example.

Is there a flip side?
Experienced users should be clear on one thing: the large quantity of liquid in the case also involves risks. Much damage could occur, for example, in case of an oil leak - water would be a much lesser evil in this scenario, but due to the free ions it cannot be used. Even the smallest of impurities lead therefore to ionizing, followed by leak currents. When exchanging components, all of the oil might have to be drained and the hardware cleaned. That is why we mounted a rubber stopper on the floor of our case to aide in emptying.
The aggressiveness of individual types of oil (above all those with a high fatty acid content) when it comes to plastics should not be taken lightly. For simplicity's sake, we decided on vegetable oil - but we recommend motor oil.

If you want to flee the daily routine and have long seen enough of everyday modding junk, this trulyunique DIY project should offer some excitement in your life.