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PostPosted: Mon Aug 12, 2002 2:32 pm 
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Hopefully this isn't a repost: <!-- BBCode Start --><A HREF="http://www.aapspower.com/abpowsup.html" TARGET="_blank">power requirements chart</A><!-- BBCode End -->. This could also be interpreted as the worst-case heat dissipation, and you could roughly estimate where the heat comes from. <br> <br>A few observations: <br> <br>1) The CD-ROM drive can get VERY hot, and heat up the rest of the case. 32X units go up to ~17W, and 50X units hit 25W. So it's wise to stick within 32X for both heat and noise reasons. <br> <br><!-- BBCode Start --><B>UPDATED:</B><!-- BBCode End --> <br>2) Memory: I did some research, examining datasheets from Samsung, Micron, and Kingmax (for their smaller TinyBGA memory chips). What I found indicates that <!-- BBCode Start --><B>worst-case</B><!-- BBCode End --> heat dissipation equals 1W * number of chips present (for both Micron and Kingmax); in the case of Samsung, 1.5W * number of chips. So a double-sided 512MB stick would consume <!-- BBCode Start --><B>16W</B><!-- BBCode End --> for Micron(Crucial) or Kingmax, or <!-- BBCode Start --><B>24W</B><!-- BBCode End --> for Samsung. The only way to cut down is to use single-sided sticks, or fewer memory sticks. Keep in mind though, these are absolute max figures and real numbers may be lower. <br> <br>The good news is that two single-sided DIMMs are as cool as one double-sided one (all else being equal.) <br> <br><!-- BBCode Start --><B>There appears to be NO effect of (Tiny)BGA versus normal TSOP packaging on memory heat. For example, the Micron chips could be packaged either way--still consuming the same 1W max apiece.</B><!-- BBCode End --> <br> <br>3) All those PCI cards contribute, bit by bit. I wonder how much difference between my large 3COM 905B network card with the tiny, low-profile <!-- BBCode Start --><A HREF="http://catalog.belkin.com/IWCatProductPage.process?Merchant_Id=&Section_Id=2018&pcount=&Product_Id=104937&Section.Section_Path=%2FRoot%2FNetworki%2E%2E%2EndCables%2FNetworkI%2E%2E%2EaceCards%2F" TARGET="_blank">Belkin NIC</A><!-- BBCode End -->. <br> <br>4) All the power added up gets divided by the PSU's efficiency. 66% efficiency means 1.5X more power, with the excess 0.5X being PSU heat from AC/DC conversion. So a savings of 10W of device usage really translates into 15W cumulative heat savings. <br>

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PostPosted: Mon Aug 12, 2002 2:32 pm 
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Hey that's very useful info, especially for those putting together big elaborate systems. I've found similar info at Intel, but buried in 100+ page PDF tech docs nobody really wants to wade through. Thanks Leo!
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