Modding my IBM server

martinlk · Post by **martinlk** » Tue Feb 01, 2005 2:39 am

Hi everybody

I recently got my hands on an IBM computer that's going to replace my current Linux server. The reason for this is that it's very small compared to my old standard size server. The new machine is a Pentium III 733MHz. It's going to bw running Debian GNU/Linux. Have a look:

So I plugged it in and turned it on. It was loud as hell! So I opened the case to try and figure out what could be done. Here's what the guts look like:

First of all, the hard drive was pretty loud. That's not a problem since I have an old Barracuda IV I can pop in there. There are two fans inside the case: a 50mm CPU fan and a 60mm PSU fan. At first I thought that I'd probably never get this thing silenced since I probably couldn't replace the PSU fan with something silent (since it *has* to be 60mm). I yanked the power from the hard drive and turned on the machine. I realized, to my surprise, that as soon as i put my finger on the CPU fan to stop it, the system was practically inaudible. So it turned out that the 60mm PSU fan was running at a low rpm count, and I don't need to replace it because it makes almost no noise at all.

This leaves only one problem to be fixed: the CPU fan! Let's have a closer look:

It get's pretty cramped in there. I have a temperature controlled CPU cooler from Arctic Cooling that's very quiet, but it's WAY too big to fit in there. So what can I do? I was thinking of removing the fan and cutting a 80mm hole in the case, allowing me to place a 80mm fan directly over the heatsink. This way, a fan would fit and it wouldn't be placed directly against the case wall (because of the hole that will be cut in it). What do you think?

Since the fan is going to be sucking air inside the case and onto the heatsink, I'm probably going to have to install and air filter as well, right?

ChucuSCAD · Post by **ChucuSCAD** » Tue Feb 01, 2005 5:30 am

How does that cover come off? If it lifts straight off you could simply cut a larger hole and mount a nice size sink/fan on it and let the whole mess stick out of the case. Then you could just gasket the hole to minimize air escape.

If the case slides off to the front or some such way that prevents the above mentioned method I would look for copper 1U or 2U S370 heatsinks, depending on the height available. Then I would go with your plan of cutting a fan hole and mounting the fan to the outside of your case, be sure to use some rubber ears and I would suggest a fan controller so you can dial in the best / lowest RPM you can get.

chucuSCAD

martinlk · Post by **martinlk** » Tue Feb 01, 2005 7:48 am

ChucuSCAD wrote:How does that cover come off? If it lifts straight off you could simply cut a larger hole and mount a nice size sink/fan on it and let the whole mess stick out of the case. Then you could just gasket the hole to minimize air escape.

You have to slide to cover towards the front a little and then you can simply lift it off. I have to say that I'm looking for a nice-looking solution to this problem, and not something that sticks out of the case.

ChucuSCAD wrote:If the case slides off to the front or some such way that prevents the above mentioned method I would look for copper 1U or 2U S370 heatsinks, depending on the height available. Then I would go with your plan of cutting a fan hole and mounting the fan to the outside of your case, be sure to use some rubber ears and I would suggest a fan controller so you can dial in the best / lowest RPM you can get.

My plan was to mount the fan *inside* the case. And about those 1u heatsinks: I'm not sure whether such a heatsink would fit. If you look at the photo of the CPU socket above you will see that there isn't much room for a heatsink that is wider than the actual socket (because of the electronics obstructing).

I guess what I'm asking is whether it would be a good idea to drill a 80mm hole in the case and attach a 80mm fan on the case lid directly under this hole (on the inside of the case). I think the fan would just barely fit, and that's why I think drilling a hole is necessary. And which way should the fan be blowing? Should it suck air into the case and onto the heatsink or should it suck air out of the case? If I suck air into the case I would probably need a dust filter as well, right?

ChucuSCAD · Post by **ChucuSCAD** » Tue Feb 01, 2005 8:05 pm

Ok I must of missunderstood you. I would cut the hole and see what happens. If you arn't getting the cooling you require you can move to a 1U or 2U all copper heatsink like this they arn't going to be any bigger then the CPU itself.

I would have the fan blowing down unless you plan on building a duct so that if the fan where sucking air it is forcing it to suck air through the heatsink. I am personally not a fan of filters and would skip it myself.

chucuSCAD

martinlk · Post by **martinlk** » Wed Feb 02, 2005 5:44 am

ChucuSCAD wrote:Ok I must of missunderstood you. I would cut the hole and see what happens. If you arn't getting the cooling you require you can move to a 1U or 2U all copper heatsink like this they arn't going to be any bigger then the CPU itself.

Not enough cooling? The only thing that's going to be different to how it is now, is the fact that I'm putting in a bigger fan. Shouldn't this cool the heatsink more effeciently?

ChucuSCAD wrote:I would have the fan blowing down unless you plan on building a duct so that if the fan where sucking air it is forcing it to suck air through the heatsink. I am personally not a fan of filters and would skip it myself.

I'm not plannig on building a duct. Why aren't you a fan of filters? Remember that this machine is a server and it's going to be turned on 24/7. I imagine that quite a lot of dust will gather up inside the case since there'll be a fan sucking the outside air directly into the case. How about installing a filter like this where you can clean the filter without removing the case lid.