Sunday, April 15, 2007

Dell goes BTX

Dell is todays subject. An aquaintence of mine recently was hired by Dell as a service tech. During his training and orientation he learned some interesting things he has shared. It seems Dell has decided to change over from ATX form factor to BTX form factor. My reply was:


For those that are not familiar with it, BTX is a 'new' form factor introduced by Intel about three years ago. It professed to solve a number of heat problems inherent with the ATX standard. The computer enthusiast community (custom builders and hobbiests) responded to this introduction with a huge yawn. BTX repositions everything on the motherboard for what Intel considers 'proper' cooling. First, they mounted the board on the left side of the case, so that the graphics card would be 'right side up' allowing heat to flow away from the GPU, instead of into the board - good idea, actually. Next they placed the CPU directly in front of the intake fan with a shroud around it, and the Chipset is placed directly behind it. So the air flows over the CPU, then the Chipset, and then out to the rest of the components. Sounds like a good idea, as long as you don't think about it any further than that.

So whats wrong with this idea?

Simple thermodynamics, thats what. For maximum cooling effect you need to maximize the temperature differential between the air stream and the object being cooled. When cooling multiple objects with a single air stream you need to consider the amount of heat coming off each item and cool from smallest to largest - because the smaller items (like the chipset) have less effect on the air stream, resulting in a larger average temperature differential overall. If you place the largest object first (like the CPU) you end up with a much hotter air stream at the end of your cooling path, lessening the cooling effect as you progress. Sure, the CPU is going to be cooler, but everything else is going to be warmer. With todays high performance chipsets, that can be a real problem.

The enthusiast community, led by overclockers, recognized this flaw immediately - hence the lack of interest in BTX over the last two years. Apparently Intel has a lot invested in this idea, so rather than letting it die a quiet death, (like the Itanium) they decided to foist it on the market by convincing (or maybe bullying) Dell into converting over. And Dell apparently has bought the idea (or capitulated).

Lets hope the other big manufacturers don't follow suit.

Forbidden PC


Chad said...

Gateway has went BTX too.

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