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Amiga News and Community Announcements => Amiga News and Community Announcements => Amiga Hardware News => Topic started by: Eric_Z on February 11, 2003, 12:56:12 PM

Title: Official 7457 7447 PDF factsheet
Post by: Eric_Z on February 11, 2003, 12:56:12 PM
PDF (http://e-www.motorola.com/brdata/PDFDB/docs/MPC7457FS.pdf)

What I find interesting is that the'll be available with 133Mhz fsb, thus we'll  be able to use them with our current line of boards.


Title: Re: Official 7457 7447 PDF factsheet
Post by: Ami603 on February 11, 2003, 03:44:29 PM
Nice info!,
Hope it will reach the correct people,as we users don`t care much about it,but Hear,developers!!!
:-D:-D:-D:-D:-D:-D:-D
Title: Re: Official 7457 7447 PDF factsheet
Post by: jumpship on February 11, 2003, 04:29:05 PM
What I find interesting is the low power 1GHz model only consums 7.5Watts of power! That should be next to no heat output, I would have thought a simple heat sink should do for that, not even needing a fan....
 mmmm....
silence...
mmmm
Title: Re: Official 7457 7447 PDF factsheet
Post by: asian1 on February 11, 2003, 04:37:03 PM
Hello
On the document they mention pin to pin compatibility with older PowerPC CPUs. Is it possible to create CPU modules for AmigaOne based on the new CPU?

With 3000 MIPS performance, perhaps comparable to P4 at 2 GHz (Clibench Dhrystone MIPS 2.1).
However Sissoft Sandra Result: P4 2 GHz at 4000+ MIPS.

But comparing MIPS on 2 different architecture (X86 and PowerPC) is very difficult, similar to comparing Apple & Orange.

Clibench (http://clibench.daemonware.ch/)

Comparison (http://translate.google.com/translate?hl=en&sl=es&u=http://www.baluma.com/OVER/p4northwood/home3.asp&prev=/search%3Fq%3D%252Bclibench%2B%252B%2522Pentium%2B4%2522%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26sa%3DG)

Complete Comparison (http://www.tahi.org/lcna/docs/cpu-performance/processor.html)
Title: Re: Official 7457 7447 PDF factsheet
Post by: System on February 11, 2003, 06:15:06 PM
Quote
But comparing MIPS on 2 different architecture (X86 and PowerPC) is very difficult, similar to comparing Apple & Orange.


MIPS is a meaningless benchmark, whether it compares x86 vs PPC or x86 vs x86.
Title: Re: Official 7457 7447 PDF factsheet
Post by: Herewegoagain on February 11, 2003, 06:29:06 PM
I thought Motorola got past 1GHz a long time ago.  It's a shame they seem to be stuck there, just like they did at 500MHz.  They should be at 2GHz by now in order to still look attractive.  And before anyone tells me, I know, the MHz/GHz myth..... but it still makes an impression on "Average Joe's" decision making.
Title: Re: Official 7457 7447 PDF factsheet
Post by: peroxidechicken on February 11, 2003, 11:59:36 PM
Has anyone else noticed that Apple are using up to 333MHz ddr ram in their new G4 systems?  Is it just for appearances sake or can the G4 actually use memory at that speed?  

And while I'm asking, are people serious when they say ppc assembler is nicer than 68k?  ppc is cryptic!  Or is it just the people who try to explain it?
Title: Re: Official 7457 7447 PDF factsheet
Post by: Orgin on February 12, 2003, 08:14:33 AM
@peroxidechicken

It's not just the CPU that benefits from faster memory. The whole systems benefits from using memory that is faster than what the cpu can handle when it is operating at maximum speed.

Example:
If the memory would operate at the same speed as the CPU and a DMA transfer from a PCI/AGP card comes in to the picture when the cpu is using memory  then there will be a severe speed penalty for both of them.

If the memory would operate at a higher speed then the penalty would be decreased.

So "can the G4 actually use memory at that speed?" is a bit misleading question. It's not just about the CPU, it's the system as a whole. The North gate is the central station for handling memory requests on a modern system. And the faster memory it can handle the faster it can share the memory resources between the different parts in the system.

/Björn
Title: Re: Official 7457 7447 PDF factsheet
Post by: KennyR on February 12, 2003, 11:25:03 AM
PPC are a family of processors that don't benefit or lose much from fast or slow memory speed. A relatively large cache and lots of registers make sure of this. Compare this to the x86, which will take a huge performance hit unless it gets fast memory to chew up.
Title: Re: Official 7457 7447 PDF factsheet
Post by: Elektro on February 12, 2003, 01:18:44 PM
Still, no DDR support is crappy. If not for speed then marketing reasons. Even ARM has it.
Title: Re: Official 7457 7447 PDF factsheet
Post by: Hammer on February 12, 2003, 11:08:00 PM
@asian1

The ideal comparisons would be based on real life applications and entertainment titles.
Title: Re: Official 7457 7447 PDF factsheet
Post by: Eric_Z on February 13, 2003, 09:19:38 AM
@Herewegoagain


Well... both yes and no.

Motorola provides Apple with 7455s that are overclocked, otherwise they only scale to 1Ghz. Or to put it in anoter way the current 7455s provided to Apple are overclocked by 42% (mac fans deny this claiming that the CPUs have been alterd for higher clockspeeds, I call this making adjustment so that the CPU dosen't fry when you overclock it).
Now what happens if you overclock a 7457 by 42% ,assuming that the 7455 and 7457 can be "equally overclocked", you get a proc running at 1.84Ghz overclock it by 25% and you get 1.6 Ghz. And last of all lets not forget that the 7457 has got 100% larger L2 cache then the 7455 (and the 7451 for that matter).
Title: Re: Official 7457 7447 PDF factsheet
Post by: BlackMonk on February 13, 2003, 08:50:12 PM
The Apple DDR systems are just a bandaid on a bigger problem.

The G4 FSB/interface to the rest of the system is only 166 MHz.  Right now the G4 and the vaunted Altivec units are bandwidth-starved.

The newer Macs use 333MHz DDR SDRAM, sure, but that doesn't help the CPU at all... and in fact I believe it incurs a bit of a latency penality compared to regular SDRAM.

The faster memory on the Macs help with PCI cards that can bypass the CPU for their operations or use the memory to buffer stuff like video data or writing video data directly to a SCSI HDD or something of the sort.  It all still goes through that bottleneck that is the G4 CPU's FSB, though.

If anything, the DDR memory only exposes more of what's currently wrong with the G4 as compared to any other modern CPU or system architecture.