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Daystar PowerCache 50MHz Socketed Accelerator HEAT

Posted by: JDW on 2019-05-07 06:02:12 I had my SE/30 running for only about an hour today (to test my Xceed PDS video card with an external VGA 17" display) and I pulled the motherboard to take some photos of my ROMinator II Mega.  My hand touched the top of the CPU and FPU and quite nearly got burned.  It's rather surprising these chips don't need to be heat-sinked.  They was a huge amount of heat coming off the board.  Just holding my hand above the board I could feel the heat flow up.  How hot are these chips allowed to get?

Posted by: BadGoldEagle on 2019-05-07 06:58:51 I don't know but my initial guess would be 105 Celsius maximum... Your discovery is quite worrying as I too have one of these.  Time to break out the IR temp gun? PS: I haven't got any pictures of mine (I used your magnificent pictures when I needed to point out something. Don't worry, I credited your work in my posts.) but I didn't know your board had a CPU rated at 40MHz and not 50! Could that partially explain the heat? But then your FPU is rated at 50MHz... so I really don't know.

Posted by: EvilCapitalist on 2019-05-07 07:16:54 You've got a 40MHz CPU, which might be the problem...assuming the board is running that 40MHz CPU 25% overclocked because of the 50MHz oscillator.  I've never felt mine to be all that hot after use, but then again it takes a bit of fiddling to remove everything connected to the board before I can remove it so perhaps that gives it a chance to cool down.

Posted by: Byrd on 2019-05-07 16:03:05 It's not crashing, so it's probably OK, but for your piece of mind I'd add a small heatsink to the '030 using some thermal epoxy (which can be removed if the need arises without damage).

Posted by: JDW on 2019-05-07 16:29:42  Easier said than done. Keep in mind this  accelerator board is sitting atop the motherboard and at the top of the motherboard is very close the bottom of the metal case. In other words, there really isn’t much space at all to add a heat sink.

Posted by: JDW on 2019-05-07 17:24:35 I know the CPU is rated at 40MHz and it is being overclocked, but it works at the 50MHz frequency just fine.  And to my fingers, the CPU gets as hot as the 50MHz rated FPU.  So I don't think overclocking is an issue.  Indeed, I think the chips are speed rated not because faster rated chips handle heat better, but because at the time of manufacture, some chips fail to work at higher frequencies, so they just stamp them differently than higher rated chips.  But sometimes lower rated chips can work at higher frequencies, as is the case with my CPU.  But again, to my fingers, the CPU gets as hot as the FPU, and the FPU is rated at 50MHz. As to the use of thermal epoxy, I have a bad experience with that.  Many years ago, I exchange dialog on Cubeowner.com with others about upgrading the video card on my G4 Cube to a GeForce 3.  I swapped out the stock heatsink with a ThermalTake copper heatsink and fan, using Arctic Silver thermal adhesive.  The video card died only days later.  Of course, that GPU needed a heatsink whereas the CPU and GPU of this accelerator technically do not, but it still worries me.  And the fact is, if one wants to add a heatsink, thermal adhesive (epoxy) is the only way to do it, assuming that heatsink would even fit.  And using of such a tiny heatsink (a couple RAM heatsinks?) may not make much of a difference anyway. As to using my photos, you gentlemen are free to do so without attribution.  There's too much of this "give me money" or "credit me" stuff these days.  Sometimes we ought to just share and enjoy the fact we've helped somebody out.  If my photos can do that for some of you, that makes me feel great.  And that great feeling is thanks enough.  But for those of you who have credited me, I don't treat that flippantly.  Thank you for your kindness.

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