By: Wilco (Wilco.Dijkstra.delete@this.ntlworld.com), August 9, 2014 12:49 pm
Room: Moderated Discussions
Michael S (already5chosen.delete@this.yahoo.com) on August 9, 2014 12:38 pm wrote:
> anon (no.delete@this.thank.you) on August 9, 2014 10:17 am wrote:
> > juanrga (nospam.delete@this.juanrga.com) on August 9, 2014 6:43 am wrote:
> > > Aaron Spink (aaronspink.delete@this.notearthlink.net) on August 9, 2014 3:44 am wrote:
> > > > juanrga (nospam.delete@this.juanrga.com) on August 8, 2014 10:49 am wrote:
> > > >
> > > > > Take a modern A57 core. According to AMD the A57 Opteron is faster than jaguar based Opteron but
> > > > > consumes less power. The ARM core performance is ~40% faster, and consumes roughly one half.
> > > > >
> > > > Faster at what? Its a bunch of market point pointing to nothingness.
Jaguar has about the same IPC as Cortex-A15, so is it really that hard to believe A57 is much faster?
> I can believe it. Jaguar is low-power low-frequency design with comfort zone around 1.5 GHz.
> If you take Jaguar to 2GHz (as in Opterons) it is very probable that
> it's going to lose to A57 both in power and in performance.
> That's why AMD builds overwhelming majority of their Opterons around Buldozer and Piledriver cores now and
> likely going to migrate to Steamroller in the near future. If I am not mistaken, out of dozens of Opteron
> models only 2 are based on Jaguar, i.e. even less that there are Xeon models based on Silvermont.
> And their main selling point of Jaguar-based Opterons is
> low price rather than high performance or low power.
> In fact, power-wise Jaguar-based Opterons are pretty uninteresting - 17W for
> quad-core GPU-less 2 GHz part. For comparison, Intel Avoton has 20 W octacore
> at 2.4 GHz. But the later costs (list) $171 while the former only $64.
>
> Still, although I believe it, I'd really like to see published SPECInt
> numbers for ARM-based Opterons instead of internal lab estimates.
Anand quoted 80 SPECint_rate for Seattle and 28.1 for X2150, ie. ~43% more SPECint per core. That's likely with the same uncore as AMD would reuse their existing L2/L3 cache and DRAM controllers. Note also these are old results, ARM recently updated the A57 performance estimates showing better results, and GCC work on ARM64 is obviously still ongoing, so actual results should be better than claimed.
As for power, the A57 version uses 25W while Jaguar uses 22W, so when running full-out at the same performance A57 uses 40% of the power of Jaguar (with frequency scaling it should be far better than that).
Wilco
> anon (no.delete@this.thank.you) on August 9, 2014 10:17 am wrote:
> > juanrga (nospam.delete@this.juanrga.com) on August 9, 2014 6:43 am wrote:
> > > Aaron Spink (aaronspink.delete@this.notearthlink.net) on August 9, 2014 3:44 am wrote:
> > > > juanrga (nospam.delete@this.juanrga.com) on August 8, 2014 10:49 am wrote:
> > > >
> > > > > Take a modern A57 core. According to AMD the A57 Opteron is faster than jaguar based Opteron but
> > > > > consumes less power. The ARM core performance is ~40% faster, and consumes roughly one half.
> > > > >
> > > > Faster at what? Its a bunch of market point pointing to nothingness.
Jaguar has about the same IPC as Cortex-A15, so is it really that hard to believe A57 is much faster?
> I can believe it. Jaguar is low-power low-frequency design with comfort zone around 1.5 GHz.
> If you take Jaguar to 2GHz (as in Opterons) it is very probable that
> it's going to lose to A57 both in power and in performance.
> That's why AMD builds overwhelming majority of their Opterons around Buldozer and Piledriver cores now and
> likely going to migrate to Steamroller in the near future. If I am not mistaken, out of dozens of Opteron
> models only 2 are based on Jaguar, i.e. even less that there are Xeon models based on Silvermont.
> And their main selling point of Jaguar-based Opterons is
> low price rather than high performance or low power.
> In fact, power-wise Jaguar-based Opterons are pretty uninteresting - 17W for
> quad-core GPU-less 2 GHz part. For comparison, Intel Avoton has 20 W octacore
> at 2.4 GHz. But the later costs (list) $171 while the former only $64.
>
> Still, although I believe it, I'd really like to see published SPECInt
> numbers for ARM-based Opterons instead of internal lab estimates.
Anand quoted 80 SPECint_rate for Seattle and 28.1 for X2150, ie. ~43% more SPECint per core. That's likely with the same uncore as AMD would reuse their existing L2/L3 cache and DRAM controllers. Note also these are old results, ARM recently updated the A57 performance estimates showing better results, and GCC work on ARM64 is obviously still ongoing, so actual results should be better than claimed.
As for power, the A57 version uses 25W while Jaguar uses 22W, so when running full-out at the same performance A57 uses 40% of the power of Jaguar (with frequency scaling it should be far better than that).
Wilco
