p4 heat shield

have searched but not found any info about this:

whats the purpose of the hole in the corner in the P4 heat shield? and more importantly, is it a problem if thermal paste gets in there? if using stock intel cooler, its kind of inevitable that the hole gets filled up with material from their thermal "pad", should it be removed or left alone if you switch to a different cooler.

tia
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More about heat shield
  1. Thats to make sure that you installed the CPU in the propper postion...

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  2. A hole is to let things get trough... :wink:

    Obviously, they need to be able to let air get trough. If there wasn't a hole, the air around the hot die would expand so much that the heat spreader would be popped off. With the hole, any overpressure can escape by forcing a way trough the thermal paste and heatsink.

    Another related explanation could be that it's easier to assemble it. Then can first apply the black glue for the heatspreader, and then press it on without capturing the air, which would otherwise push the heatspreader up again while the glue is still drying.

    And don't worry if any thermal paste gets stuck in it.
  3. theres a missing pin and a notched corner.. we needed a hole in the heat shield as well to tell us that it only goes in one way? :)

    so back to the other question.. is it safe to have it clogged with old thermal interface material or no?
  4. >Obviously, they need to be able to let air get trough.

    You may want to rethink that. how much air do you think will get through with a heatsink and thermal paste applied around the hole ? If anything would get through, the heatsink would be performing miserably. the whole point of thermal past is to eliminate microscopic small air 'buckets'.

    >Another related explanation could be that it's easier to
    >assemble it.

    Sounds more likely to me.

    = The views stated herein are my personal views, and not necessarily the views of my wife. =
  5. seems to me that hole could have much easyer been a notch in the side of the spreader.

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  6. thanks for all the replies, some good ideas, but it all looks like speculation, still hoping for some concrete technical info on this.

    i'd also like to point out that AMD's new 64bit cpu's have a heat shield with no hole.
  7. Quote:
    You may want to rethink that. how much air do you think will get through with a heatsink and thermal paste applied around the hole ? If anything would get through, the heatsink would be performing miserably. the whole point of thermal past is to eliminate microscopic small air 'buckets'.

    I still think it's a very plausible explanation. First of all, Intel itself doesn't really use paste, but a pad. Just a little canal in it would be enough to let the little bit of air escape. With more viscous pastes, this might be more of a problem. Secondly, a Pentium 4 can very well handle some "air buckets" with this big heat spreading area. And last but not least, air can get trough nearly everything if there's enought pressure and you wait long enough. Every time your CPU heats up, a tiny bit of the air could escape. After a while, you even create a little vacuum when the CPU cools down, so this also explains the phenomenon that when you remove your heat sink, you often also pull the CPU out of its socket...
  8. I disagree.. the idea of having a hole to enable hot air to expand makes sense, but such a hole would really be placed on the side, and not on top where the paste+heatsink creates an airtight barrier.

    >First of all, Intel itself doesn't really use paste, but a
    >pad.

    the pad melts upon first use, and spreads out all over the heatsink. Its not like it remains like that for longer than a few seconds or so. after it has melted, it isnt too different from regular paste.

    > Just a little canal in it would be enough to let the
    > little bit of air escape.

    Just imagine how the air in that "canal" would heat up ! really, HSF manufacturers try their best to make those heatsink bottom near perfect mirrors, with the sole reason of eliminating as much as possible any air trapped between the cpu (or heatspreader) and the heatsink. thermal paste does the rest.. you are talking about microscopic small ammounts of air here that are already a problem they try to evade.. an air duct would really totally ruin such efforts.

    >Secondly, a Pentium 4 can very well handle some "air
    >buckets" with this big heat spreading area.

    I'm not too sure.. it does create hotspots, and I don't see how the P4 is immune to this. Its not like the fastest P4's out there are only getting luke warm and would only need small coolers..

    > After a while, you even create a little vacuum when the
    >CPU cools down, so this also explains the phenomenon that
    >when you remove your heat sink, you often also pull the CPU
    >out of its socket..

    Yeah, but if its a vacuum, it means air can't get in. When it can't get in, it probably can't get out either.

    = The views stated herein are my personal views, and not necessarily the views of my wife. =
  9. I just found this:
    <A HREF="http://www.ocfaq.com/article.php/overclocking/intel/37" target="_new">http://www.ocfaq.com/article.php/overclocking/intel/37</A>

    "The hole in the P4's heat spreader is a result of the manufacturing process. The IHS is glued to the processor substrate with epoxy at the Intel plant. The hole allows gases and pressure to escape while the epoxy cures. Without the hole the pressure would deform the epoxy bond and make the connection between substrate and IHS uneven.

    It is perfectly safe to cover and/or fill it with thermal paste."

    I guess that answers it.

    = The views stated herein are my personal views, and not necessarily the views of my wife. =
  10. sweet, thanks very much bb..

    (now i still wonders how AMD gets around this little technical hurdle without having a hole, but I don't have any AMD's with heat shields, so I don't so much care :tongue: )
  11. you do relise a heat spreader and a heat sheild or totally opposite things.

    BTW bb the material under the IHS is pretty hard when cold even after the cpu has run many times it still returns to a solid state.

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  12. > bb the material under the IHS is pretty hard when cold
    >even after the cpu has run many times it still returns to a
    >solid state

    You mean the thermal pad I assume ? I wouldnt know honestly, since I've never used it, I would always immediately replace it with AS :) Still, hard or not, I would assume it would melt when hot, and spread all over the surface and become a very thin layer. I can't imagine such a pad being a full millimeter thick like it is before you use it; and as such, it wouldnt be too different from paste.. at least that's what I would think.

    = The views stated herein are my personal views, and not necessarily the views of my wife. =
  13. yeah, my terminology may be off on this one, but i'm pretty sure we are all talking about the metal peice that covers the core (and has a hole in it on p4's). that diagram from the link labels it as a heat spreader, but i've always seen it called a heat shield around the net...

    so from now on I suggest we call it "heat shprield" :tongue:
  14. I think he is referring the thermal interface material that is in between the core and the heat spreader, placed there lovingly by intel's robotic arms. (I assume its done by robotic arms, it damned well better be done lovingly).
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