ARM announces A72

By: Wilco (Wilco.Dijkstra.delete@this.ntlworld.com), February 4, 2015 4:01 pm
Room: Moderated Discussions
juanrga (nospam.delete@this.juanrga.com) on February 4, 2015 5:23 am wrote:
> Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on February 4, 2015 1:58 am wrote:
> > juanrga (nospam.delete@this.juanrga.com) on February 3, 2015 5:15 pm wrote:
> > > Hugo Décharnes (hdecharn.delete@this.outlook.fr) on February 3, 2015 2:20 pm wrote:
> > > > Cortex-A57 delivers better performances than Cortex-A15, though their micro-architectures
> > > > are–nearly–identical. We'll see if ARM Ltd. reiterates with Cortex-A72.
> > >
> > > More than 80% performance gains over A57.
> >
> > ... but it was clearly stated that this is at the same mobile power
> > budget. So the gains are from improved power efficiency.
> >
> > > ~50% IPC gain over A57, rest from ~30% higher clocks.
> >
> > I didn't read anything that indicated such a huge IPC gain. Peak performance should be much better of
> > course, but much of that will be due to higher frequencies enabled by the improved power efficiency.
> >
> > Wilco
> >
> >
>
> I did read the preliminary analysis here
>
> http://techreport.com/news/27767/arm-unveils-cortex-a72-cpu-mali-t880-graphics-and-more

That analysis is wrong, ignoring the fact that the comparison is at identical power, not at max frequency. The large gain in power efficiency allows the A72 to run at a higher frequency than A57 or A15, even on the same process. That means the 80% benefit is split between frequency gains enabled by lower power on the same process, frequency gains due to FinFet and IPC gains. Let's say the average IPC gain is 20% (probably not far off given the range Peter mentioned), so that means the frequency gain is 50% (1.5 * 1.2 = 1.8, something else Techreport got wrong).

Wilco
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TopicPosted ByDate
ARM announces A72Maynard Handley2015/02/03 12:36 PM
  ARM announces A72anon2015/02/03 01:53 PM
    ARM announces A72Hugo Décharnes2015/02/03 02:20 PM
      ARM announces A72juanrga2015/02/03 05:15 PM
        ARM announces A72Wilco2015/02/04 01:58 AM
          ARM announces A72Eric Bron2015/02/04 02:48 AM
            ARM announces A72none2015/02/04 03:24 AM
              ARM announces A72Eric Bron2015/02/04 03:42 AM
                ARM announces A72Exophase2015/02/04 08:01 AM
                  ARM announces A72Anon2015/02/04 08:35 AM
                    ARM announces A72Exophase2015/02/04 08:58 AM
                      ARM announces A72Groo2015/02/04 10:24 AM
                ARM Marketing, BS up to my earsDavid Kanter2015/02/04 11:51 AM
                  ARM Marketing, BS up to my earsMaynard Handley2015/02/04 02:59 PM
                    ARM Marketing, BS up to my earsDavid Kanter2015/02/04 03:21 PM
                  ARM Marketing, BS up to my earsGroo2015/02/04 03:30 PM
          ARM announces A72juanrga2015/02/04 05:23 AM
            ARM announces A72Wilco2015/02/04 04:01 PM
              ARM announces A72juanrga2015/02/04 05:06 PM
        ARM announces A72Anon2015/02/04 02:28 AM
          ARM announces A72juanrga2015/02/04 05:31 AM
            ARM announces A72Aaron Spink2015/02/04 07:49 AM
      ARM announces A72Ronald Maas2015/02/03 08:23 PM
        ARM announces A72Seni2015/02/04 01:19 AM
          ARM announces A72Maynard Handley2015/02/04 11:42 AM
            ARM announces A72Seni2015/02/04 01:33 PM
              ARM announces A72dmcq2015/02/04 01:57 PM
            ARM announces A72Ronald Maas2015/02/04 07:42 PM
        ARM announces A72anon2015/02/04 06:19 AM
          ARM announces A72Exophase2015/02/04 08:31 AM
            ARM announces A72David Kanter2015/02/04 11:25 AM
              ARM announces A72Exophase2015/02/04 02:33 PM
                ARM announces A72anon2015/02/04 11:27 PM
                  ARM announces A72 (fixed format)anon2015/02/04 11:29 PM
                  ARM announces A72Exophase2015/02/05 12:11 AM
                    ARM announces A72anon2015/02/05 01:02 AM
            ARM announces A72anon2015/02/04 06:57 PM
  ARM announces A72Wilco2015/02/03 02:39 PM
    ARM announces A72Maynard Handley2015/02/03 03:13 PM
      ARM announces A72anon2015/02/03 03:29 PM
      ARM announces A72Wilco2015/02/03 03:44 PM
    ARM announces A72David Kanter2015/02/04 10:56 AM
      ARM announces A72Peter Greenhalgh2015/02/04 11:56 AM
        ARM announces A72Aaron Spink2015/02/04 12:59 PM
          ARM announces A72Alberto2015/02/07 11:22 AM
            ARM announces A72Exophase2015/02/07 11:47 AM
              ARM announces A72Alberto2015/02/07 01:44 PM
                ARM announces A72Exophase2015/02/07 03:35 PM
                  ARM announces A72Alberto2015/02/08 02:09 AM
                    ARM announces A72Exophase2015/02/08 12:05 PM
              ARM announces A72David Kanter2015/02/08 01:39 AM
                ARM announces A72dmcq2015/02/08 05:14 AM
                  ARM announces A72Michael S2015/02/08 05:38 AM
                    ARM announces A72Gabriele Svelto2015/02/10 06:11 AM
                      ARM announces A72Jouni Osmala2015/02/10 12:24 PM
                        slit vs unifiedMichael S2015/02/10 02:57 PM
                          slit vs unifieddmcq2015/02/11 06:44 AM
                  ARM announces A72Doug S2015/02/08 10:00 AM
                ARM announces A72Exophase2015/02/08 11:57 AM
        ARM announces A72dmcq2015/02/04 02:10 PM
        ARM announces A72David Kanter2015/02/04 03:28 PM
      ARM announces A72Wilco2015/02/04 02:59 PM
        ARM announces A72Aaron Spink2015/02/04 10:31 PM
        Intel 32nm vs 14 nmMichael S2015/02/05 02:03 AM
          Intel 32nm vs 14 nmWilco2015/02/05 03:27 AM
            Intel 32nm vs 14 nmDavid Kanter2015/02/05 10:05 AM
              Intel 32nm vs 14 nmcarop2015/02/05 12:12 PM
                Normalize to drawn or effective width?David Kanter2015/02/05 12:45 PM
                  Normalize to drawn or effective width?carop2015/02/05 03:40 PM
                    Normalize to drawn or effective width?David Kanter2015/02/06 01:44 PM
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