Keeping It Cool

PC cabinets are just boxes that hold our components, and keeping it cool is only a matter of adding fans, right? wrong!

It all started when a colleague wanted to show off his latest geek-venture. Working for Digit, it’s tradition to show off the latest gizmos and gadgets. This particular colleague hadn’t bought anything new-he’d just added a lot of fans to his cabinet, and was now claiming to have the coolest cabinet in town. We counted 12 fans in all-overkill for sure! However, what he didn’t know was that his 12 fans were not helping much…

All About Airflow
Keeping a cabinet cool isn’t as simple as just adding an obscene number of fans on the top, back, front and side. What you need to focus on, when improving cooling is how the air flows, and how you can make sure that cool air hits the components that get hot. Now some case-modders have done crazy things, like integrating table fans into their cabinets, so powerful that you see IDE cables flapping in the breeze, or there are those that use liquid cooling… however, most of us are tech-crazy, not stark raving mad! Our colleague had some intake fans right next to exhausts, which was defeating his purpose.

Since we were planning on starting a series of DIY articles, we figured we might as well start with cabinet cooling and airflow.

Thinking about this article, the very first problem that cropped up was, how do we show airflow? Now we could go out and get expensive smoke machines to fill the cabinet with smoke and see where the air went, but how would that help you? A DIY needs to be simple, and needs to lend itself to easily replication at the average home.

Also, we often get carried away and tend to use the best hardware for everything, but in order to stay in touch with real-world scenarios, we were forced to curb our enthusiasms, and work with an everyday, run-of-the-mill PC setup.

Another restriction we set upon ourselves was the money we were allowed to spend on this little project. A budget of Rs 1,000 was allocated, because we figured there’s no way the average Digit reader would be willing to spend more than that on just cooling his or her regular cabinet.

With these things in mind, we set off to our neck of the computer component woods called Lamington Road. We bought three cabinet fans, Rs 50 each; a hard disk cooler, Rs 350; one round IDE cable for a slightly steep Rs 400 (thankfully, they come bundled with most new motherboards), and then overshot our budget even more, splurging on a little tube of Arctic Silver thermal paste, Rs 400! The Arctic Silver is completely unnecessary for most of you, especially if you’re not overclocking your CPUs or GPUs, so forgive us our little indulgence. We also bought a little hand blower for Rs 15 to get rid of accumulated dust.

Smoke Screens
The 12-fan-colleague, mentioned earlier, was shown the folly of his ways using cigarette smoke; however, it’s not like Digit wants to encourage its readers to take up a bad habit like smoking just to solve airflow problems-we get enough mails from angry parents as it is! So we decided to use incense, the type that most of India uses in prayers and rituals. It’s called dhoop here, but anything that gives off a lot of smoke will do. Just make sure it doesn’t give off too much heat, or you’ll end up scorching your eyebrows, or worse still, your cabinet or SATA/IDE cables!

It isn’t as descriptive as it seeing it live, but the smoke from the incense sticks is fairly indicative as to how air flows in the top section of the cabinet. What you can’t see here is the smoke being blown out the sides of the processor heatsink and then sucked and expunged by the power supply

Note: You should know that we did leave black charred marks in our white cabinet, and at least one person burnt his fingers, so be careful.

The PC
We used a regular-looking cabinet, and tried to recreate an average PC configuration to generate the type of heat that most of you should have within your cabinet.

The configuration was:

In order to be able to show you the smoke / airflow, we also went out and bought a clear acrylic sheet for Rs 80. You can do this yourself as well, to keep the innards of your cabinet visible at all times.

The only thing we didn’t open in search for dust was the SMPS, which was still within the warranty period. You should also avoid breaking any seals that can void your warranty. If all warranties have expired, don’t be afraid to open out the SMPS cover as well (after disconnecting it from the mains, obviously) to get at that cake of dust that forms within all power supplies.

Now that we had a nice, gleaming PC, we went a little off track and Arctic Silver-ed the CPU, after cleaning the old thermal paste away, and cleaning the heatsink using a cloth and some brushes between the fins. We then proceeded to connect everything back, and used the round IDE cable instead of the flat one we had earlier. We also connected the RAM strips in the slots furthest away from the CPU-you may not be allowed to do this on all motherboards-and made sure there was enough space above and below each hard drive.

We now measured the temperature again, and found that it hovered between 31 and 32 degrees celsius. That’s 2 or 3 degrees cooler just because of a sound cleaning! We also found that the CPU idling temperature from the BIOS screen had dipped from 42 degrees to 38 degrees Celsius-vive le Arctic Silver!

Now our cabinet also came with a side panel with a conical appendage on the inside that’s meant to help bring cool air directly to the CPU heatsink. We wanted to check whether this helped the CPU cool any better than when we attached the simple acrylic sheet. It did, but very marginally; with the stock cabinet side panel, with the conical appendage, we found that CPU temperatures stayed at 37 or 38 degrees; however, we suspect that airflow was obstructed by this cone, because cabinet temperatures were raised a degree.

For those of you wondering why a degree matters, you should remember that these are just idling temperatures, and also during the winter, in an air-conditioned office. At home, with cramped spaces within your computer table, or under a desk, while running a game or video-rendering software or something equally taxing, the temperatures of your CPU and cabinet will soar-even more so in
our Indian summers, for those without air conditioning!

We decided to discard the stock side panel and stick to the acrylic sheet. Not only did it seem cooler inside the cabinet, we also needed to conduct our airflow experiments now, and needed the transparency of the acrylic.
 

Round IDE Cable
A round IDE cable will help you push it to one side, and not obstruct airflow the way the flat cables do. If you have mainly IDE drives, make sure you get yourself a few round IDE cables to help air flow inside your cabinet. Unless they came bundled with your motherboard, the costs can be a little daunting, at around Rs 400. You could, however, gingerly pry out individual wires, or even pairs, from your flat IDE cable and bunch the lot together to make your own round IDE cable, as we have done here. Note that we take no responsibility if you botch up.

Coughing Fits
Now it was time for the smoke. We made the mistake of trying to conduct the experiment in a closed room-bad idea. Five minutes into the whole thing, we all ran out coughing up something terrible, and found that everything, including water, seemed to taste of incense. We strongly advise that if you do this, do it in a very well-ventilated area.

Red-eyed and with weakened lungs, we bravely ventured back into the room and opened the windows, and brought along a couple of fans.

We then proceeded to fill our cabinet with smoke, and try and see how the smoke flowed. We put a few burning incense sticks (safely contained inside a ceramic plate, after one of us burnt his fingers!) into the cabinet, put the acrylic sheet on, and then waited awhile for the cabinet to fill up with smoke. We then turned the PC on and watched where the smoke went. The hardest part was trying to get still photographs to tell the story, but to the naked eye, the way the air flowed was obvious.

Now the fan-happy colleague we mentioned earlier had inadvertently reversed his cabinet’s rear fan, causing it to draw air in instead of throwing it out! We did the same to our test cabinet, and noticed that this was bad for airflow, because everything was being forced out from the power supply exhaust. This left smoke in the lower regions of the cabinet for a few seconds longer. It was also opposing the way the CPU fan was trying to blow air out, causing our smoke to be dispersed wildly, instead of forming a nice neat channel of airflow. All of you should make sure that your cabinet’s rear fan does indeed blow air out, because if it’s acting as an input instead of an output, it could cause your cabinet to be hotter than it should be. The smoke also cleared a few other things up:

We found that the ATI Radeon X1300XL graphics card we used had active cooling, but due to its design, sent its exhaust (hot air) towards the centre of the cabinet. When we compared it to the newer design of the X1900XT, which occupies two slots but sends its exhaust directly out the back of the cabinet, we found that older graphics cards really leave a lot to be desired in terms of airflow!  

We also noticed that there was hardly any air flowing over or under the hard drives or the DVD-Writer. Now a DVD-Writer may not need cooling, but hard drives certainly do!