BTX Cooling and Airflow Explained

We know the purpose of the BTX design and why each component is placed where it is, but the question is, will it work? Will a single CPU heatsink fan be able to effectively cool all of the critical components in a system? In our preview of BTX last year we explained the placement of each component as well as showed a top view of the heat paths in a BTX system. The CPU, Northbridge, Southbridge, and VGA card are all inline which creates a single path for air to flow and in one single direction, from front to back through the thermal module.


From the picture we see the flow of air pushed back through the CPU thermal module towards the Northbridge, Southbridge, and VGA card. As this air flows around the CPU, it warms up, as we can see from the red areas to the left and right of the CPU. This warm air then flows over the Northbridge and seems to cool as it travels further back in the chassis. At the left we see the channel of air flowing to the left over the memory and out through the PSU. The channel on the right flows straight back to the VGA card and out through groups of holes in the back of the case.

Intel will incorporate various other features that will help their CPUs perform at an efficient level no matter the conditions beginning with the Pentium 4 6xx series chips scheduled for Q1 of 2005. One feature is an enhanced version of their mobile processor SpeedStep technology called just that, Enhanced SpeedStep Technology; EIST or EST. EIST will allow the operating system to lower the CPU's power state during idleness which will reduce heat dissipation and power consumption. Another feature which will have a great effect on a system's thermal conditions as well as safety is the Thermal Management feature. This feature allows the CPU to immediately cut its clock speed to a fraction of its normal operating clock speed when the motherboard detects it is operating at temperatures out of the norm.  There are a lot of Centrino-eque technologies at work here.  The lessons learned from Pentium M have played heavily on system design as well as processor design. 

So how will Intel's new BTX form factor affect third party manufacturers specializing in cooling equipment? The fact of the matter is that cooling hardware will always be required. We have seen in past ATX case reviews that no matter how many fans are in a case, a single 80mm fan at the front as an intake, or a set of six 80mm fans throughout a mid tower case, current hardware will operate under normal loads. Users, however, still prefer to spend their money on extra cooling equipment to get the most out of their systems. Intel has been bundling their heatsink fans with their CPU's since the beginning while third party manufacturers like Zalman and Thermaltake provide solutions for enthusiasts who prefer custom hardware. So the market for third part hardware will still be there for the BTX form factor as it has been for ATX.

BTX Cooling and Airflow First Look: AOpen B300 microBTX case
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  • HardwareD00d - Monday, November 15, 2004 - link

    Instead of spending all the money to research BTX, Intel should have just made watercooling standard on the Prescott CPU. Apple could have said they stole the idea from them like everything else ;)
  • Omega215D - Monday, November 15, 2004 - link

    It looks like Intel needs all the cooling it can get. I found an interesting article at Toms Hardware and here;s the closer about its heat problem "So, should a vendor release a product that is only able to run at its maximum performance under special circumstances? The fastest processors certainly are very exclusive devices, but that should not cause more troubles than necessary. The customer wants products that simply work! Think about that before releasing faster products, Intel." All I can say is wow, because I can remember my P3 866 didn't need all that cooling though now I moved on to AMD.
  • HardwareD00d - Monday, November 15, 2004 - link

    It sounds like you can essentially get the same thermal performance from an ATX case by adding 1 additional case fan.

    At least Intel has decided not to push this new form factor down peoples throats. Honestly, that's what I figured they'd try to do.
  • Gatak - Monday, November 15, 2004 - link

    To have the powersupply and drive bays at the bottom is a good thing. It will keep the temperature more balanced inside the case and also provide more room at the top for cards and for exhaust fans, rather than craming everything up there.
  • Pythias - Monday, November 15, 2004 - link

    ROFL #6!!
  • Ecmaster76 - Monday, November 15, 2004 - link

    If a retail board showed up to a review with that horrible a component layout, it would be figuratively flogged.

    I find that the review was somewhat flawed since it failed to see what would happen with a discrete graphics card in the box. If one was used, I didn't spot it in the screenshot of the full ATX or uBTX screeshots, and it wasn't mentioned in the text.

    Finally it should be mentioned that many people have theorized that the BTX layout would not work well for the Athlon64's onboard memory controller because of issues with trace layout. I'm no expert, but it does look like it might get a little tight.
  • ksherman - Monday, November 15, 2004 - link

    "Anand's *vacation* work trip to Taipei..."

    Probably one of the funniest things i have read in one of your reviews.... ;)
  • raskren - Monday, November 15, 2004 - link

    As always, so much Intel backlash, simply because, its Intel.

    This is how cases should have been done originally. Align all the hot components and put a fan in front and behind them. Makes sense, right?

    Current ATX design is "put a fan on every hot item you have". At least that's how my case is.
  • LoneWolf15 - Monday, November 15, 2004 - link

    To me, BTX looks like a winner for only one niche: small form factor business desktops. By that definition, I don't include Shuttle's wonderful SFF PC's which work best for home and HTPC enthusiasts. The microBTX form factor looks great for an office environment where quiet operation is a real plus, as well as power consumption, and since business PC's don't need to be cutting-edge, middle-end processors can be used that don't generate a lot of heat.
    Tor the enthusiast however, BTX looks like a bust to me, more of an attempt by Intel to throw the market out of whack, specifically AMD's market. Enthusiasts already have case designs meant to exhaust a lot of air and keep systems cool. Many enthusiasts LIKE a little bit larger case so that they have more expansion room, with the exception of their HTPC, and so that they can house a decent power supply for that expansion.
    I see HP, Compaq, IBM, and other mainstream business computing giants adopting BTX; it will probably do well in the business market as well as in mass retail, where OEMs would rather make a system with less fans to fail and at cheaper cost. That's a pretty big sector for profit of course, but this form factor, IMO, leaves PC enthusiasts out in the cold.
  • Beenthere - Monday, November 15, 2004 - link

    BTX is obviously NOT a great design. Intel changes sockets, Mobo and other specs periodically to FORCE people to update to their latest crap. Don't expect a rush to BTX. It's another Intel spec unlikely to ever gain foothold...

    For those who don't already know you can do wonders for ATX case cooling with "managed airflow". By actually directing incoming cool air to the heat sources and isolating the CPU fan from warm air in the case, no one really needs a BTX case and your PC will run much cooler with managed airflow.

    While Intel definitely needs a tornado inside a box to cool their defective 90 nano CPUs, the BTX standard is just another Intel marketing scam for all practical purposes.

    Just say NO !

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