Date: Thu, 29 Sep 2016 07:10:18 +0200 From: =?UTF-8?B?TWljaGHFgiBKxJlkcnplamN6YWs=?= <local@o2.pl> To: galtsev@kicp.uchicago.edu Cc: Ralf Mardorf <ralf.mardorf@rocketmail.com>, freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: i386 version in future ? Message-ID: <CANrxokF=gp5AH-PRins-v5nJtWaViHVpF1%2BLHZ5_JZMZzFU0cA@mail.gmail.com> In-Reply-To: <37046.128.135.52.6.1475074557.squirrel@cosmo.uchicago.edu> References: <CANrxokEkYLY7uTv%2BnWy4K_iBeeaaCMraJmrNOD7cU2GXCWkNCA@mail.gmail.com> <0D6BF663-5C95-4625-B412-00E14EF97986@FreeBSD.org> <35.AF.06698.BEF4AE75@dnvrco-oedge03> <20160927134158.74c11036@archlinux.localdomain> <CAOgwaMuMfF7_zve%2BAMuJ8iiAD4wMXGUQDO4-j8Ck1B1FZ=NOXA@mail.gmail.com> <20160928091109.7aa95c9d@moonstudio> <CAOgwaMs_jRzvrnCxyD1i1z8S8Q4AzbpAGC0jGEp9Y-KwdqvbVA@mail.gmail.com> <20160928105420.7b1d117f@moonstudio> <37046.128.135.52.6.1475074557.squirrel@cosmo.uchicago.edu>
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Thanks everyone for answers, now I know lot of more what I wanted :) Regards Micha=C5=82 J=C4=99drzejczak 2016-09-28 16:55 GMT+02:00 Valeri Galtsev <galtsev@kicp.uchicago.edu>: > On Wed, September 28, 2016 3:54 am, Ralf Mardorf via freebsd-questions > wrote: > > On Wed, 28 Sep 2016 00:59:09 -0700, Mehmet Erol Sanliturk wrote: > >>You are comparing different CPU brands with each other . > > > > It's unrealistic to compare 32 bit and 64 CPUs, produced with the same > level of development. Could you provide some examples? > > > > Actually I'm comparing two CPUs from the same family. The CPU I'm using > for my desktop computer today and the last 32 bit CPU I used for my > desktop computer before I switched to 64 bit. > > > > My old 32 bit was an Athlon single core 800, 850 or 900 MHz, I don't > remember exactly, Socket A, so the consumption was between >=3D 42.6 W an= d > <=3D 49.7. My current, newer 64 bit dual core is an Athlon BE-2350, 2100 > MHz, Socket AM2, 45 W. > > > >>Assume that two CPUs are produced with the SAME technology . > >>A 64 bit CPU will contain more circuits than a 32 bit CPU , means more > power it will use because amount of power will be proportional to number > of circuit components and length of connection lines . > > > > But they are not produced with the same technology, the 32 bit > > Athlon I mentioned requires 1.70 V or 1.75 V, the 64 bit Athlon I > mentioned 1.25 V, they are anyway from the same family, they were just no= t > produced with the same level of development. > > This is true: the power goes mostly into charging and discharging > capacitances associated with FET gates (ans stray capacitances). Energy > associated with charge is (C*(U)^2)/2. If we use half of voltage this > energy drops 4 times! (hence consumed power drops 4 times). This is why > the highest frequency part (core) works at lower voltage than the rest of > CPU. Now, there is also capacitance C in that formulae, which roughly > speaking is proportional to gate area (it is more sophisticated, yet...). > So, the technology goes to twice as small nanometers (which are linear > dimensions of elements), then the capacitance diminishes 4 times. That is > why it only makes sense to compare "the same technology". Next, the CPUs > are more sophisticated than just a width of arithmetic unit which for 64 > bit would be twice than for 32 bit if CPUs were trivial devices. Actually > it is not quite so, thus processing some amount of 32 bit CPU work on 64 > bin CPU will (considering the rest equal) not require to spend twice the > energy as compared to 32 bit CPU. You will spend more energy, this is > correct, but not two times more. (Very crude analogy here is: powering of= f > unused CPU cores; somewhat parallel utilization of components of 64 bit > CPU when processing 32 bit stuff probably is less crude way of saying it)= . > > Anyway, thanks, everybody for refreshing and very insightful discussion! > > Valeri > > > > > The slower CPU, slower RAM, different hardware, IDE etc., made the old > computer almost half as fast, so it needs to run almost double the time, > to reach the same processing power. > > > > https://en.wikipedia.org/wiki/List_of_CPU_power_dissipation_ > figures#AMD_Athlon_64_X2_.2F_Athlon_X2 > http://www.anandtech.com/show/557/3 > > > > Regards, > > Ralf > > _______________________________________________ > > freebsd-questions@freebsd.org mailing list > > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > > To unsubscribe, send any mail to > > "freebsd-questions-unsubscribe@freebsd.org" > > > > > ++++++++++++++++++++++++++++++++++++++++ > Valeri Galtsev > Sr System Administrator > Department of Astronomy and Astrophysics > Kavli Institute for Cosmological Physics > University of Chicago > Phone: 773-702-4247 > ++++++++++++++++++++++++++++++++++++++++ > > > > > > > > > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions- > unsubscribe@freebsd.org" >
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