Zalman MDD II

As anyone who has ever used a MDD will tell you, they get hot. And I mean Hot. Not completely Apples fault, Motorolla just could not compete (or were not inclined to compete with the likes of Intel and clock speeds/small die sizes). The result was a computer that was noisy (fans), cramped inside & hot. Also Apple's decision to put 4 Hard Drives inside, just to add to the pain of extra heat. Well with the sizes currently available of Hard drives you can easily put in a couple of 500 gig HDD's & put the space saved to some use. Before I start, I will make one thing clear, the MDD is never going to be the quietest computer around but at least we can cool it some! This is in no way intended to be the most frozen of MDD's around, but it is not impossible to do & with a bit of ingenuity & a certain amount of will!

I looked around for a Intel/AMD heatsink that would fit the bill & also fit the case. I came up with this one:

I would have to use a shim to mate up between this cooler and the actual processors. I decided to fit this to a Giga designs dual 1.33 that I would overclock to 1.5 GHz. I decided to use the same shim that I had used for my watercooling exploits for which details and dimensions are available on the download page of this site. The same process can be carried out on some Apple dual 1.25's, basically the ones that have 4 holes already available on the processor that can br used for mounting. I found some Brass strip lying around at work which was ideal for fabricating the fixing brackets. Below are shown 2 that I made for an Apple Dual 1.25. After measuring the processor fixing holes I drilled 3 x 3.5 mm holes in each brass strip. By the way, the brass strip is 12 mm wide and 3 mm thick.

I also had to cut some short lengths of Aluminium tube to act as spacers and obtain some 3 mm socket screws for fixing.

Here you can see the copper shim in between the Zalman heat sink and the processor. Also the fan can be plugged directly into the Giga processor board.

To make sure this computer stayed cool, I decided to improve on removing the air from the case, there was just enough room to squeeze in another 120x120x25 mm fan along with the Apple 120x120x35. This would remove air from the case which in the MDD seems to always get trapped!

Also, to remove the air efficiently, I used a similar design to one that I had worked out on a previous system - see below

Above - You can get an idea of the scale of this beast, it protrudes a good 25 mm above the back panel, but still allows the fitting of a 120 x 120 x 25 mm fan on the inside wall of the case, with the ability of the drop down door to still close properly.

Top view shows the airflow direction works well in the MDD case and also force feeds air to the graphics card fan, in this case a Dual DVI Fire GL X3, flashed & chip changed, running as a X850 XT.

One of the other benefits of this cooler, is that it also supplies cool air to the ram and processor mosfets which also get pretty hot with the stock Giga fan.

So there you have it, fairly straight forward MDD cooling. I don't have any temps as yet, as the Giga does not have a thermistor on board, but, it is running at 1.5 Gigs and the shim feels cool to the touch!

More advanced MDD Watercooling

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