Yea it's the chicken and the egg problem. I was thinking of devices like the 12'' macbook with sholdered ram and pretty much every ultrabook with an intel ulv that has dual channel ram sholdered or in sodimms. I guess the thermal budget issue will become less of a thing when we get to ddr4l On Tue, Mar 14, 2017 at 10:55 AM, Bill Kontos <[email protected]> wrote: > The problem right now is that pretty much none of the arm SoC manufacturers > adds what is needed for supporting a full desktop/ laptop experience, that > is more than 4 gb of ram, sata3, general purpose pcie lanes and more memory > bandwidth for the igpu.
each of those interfaces as hard macros costs around $50k to $100k to license. also the power budget is... well... see below. the licensing cost (and design NREs) for using greater than 4GB of RAM - even if ARM *actually does it* - would be cost-prohibitive. but the thing is, there's an example SoC that breaks the example that you've given: the rk3288. the rk3288 easily out-performs recent high-end intel atom systems, and can do 4GB of RAM, and is available in a *lot* of very popular chromebooks. > Most of the arm chips right now are stuck at 64 bit > ddr4 at most, and the ones we have access too ( being libre) have even less > bandwidth and are even more limited when it comes to ram. > > Just an example, going from single channel to dual channel on an intel igpu > increases performance by 20-30%, and that's even on a gpu design much worse > than any powervr or mali gpu. ... with the disadvantage that it increases the power budget (relatively) by an *enormous* amount. * 32-bit DDR3L @ 800mhz uses around 300mW * 32-bit DDR3L @ 1600mhz uses FOUR TIMES that amount - 1.2 watts. * 64-bit DDR3L @ 1600mhz uses around 2.5 watts that's just for the RAM ICs, excluding the driver power budget on the SoC itself. a 128-bit channel would be in excess of FIVE watts at 1600mhz. if you're used to working with SoCs that *don't even need a heat-sink*... so now you're in to heat-sinks, fans, extra-careful thermal design: now you're in to a $200k design, now you have to *justify* that... and there's no chinese ODM that's going to bother when they can make much more money selling tablets and phones than they can desktops and laptops *with no OS*. i realise that's a circular trap. l. _______________________________________________ arm-netbook mailing list [email protected] http://lists.phcomp.co.uk/mailman/listinfo/arm-netbook Send large attachments to [email protected]
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