[X4U] New 1.8Ghz G5 Tower in Apple Store

[Zane H. Healy]

> On Oct 19, 2004, at 13:09, Zane H. Healy wrote:
> 
> >   The FSB should be at 1/2 the speed of the CPU,
> 
> Why do you say that?  That is not true at all.
> 
> There's nothing that says that the FSB _has_ to be half of the CPU 
> speed, it just tends to be that way in the Apple product line.  It all 
> depends on the clocking.  You can have a 2:1 or 3:1 or 5:2 or whatever. 
>   If you look at Pentium or AMD CPUs and FSB speed, there's hardly a 2:1 
> to be seen.  3.4Ghz P4s don't run a 1.8Ghz FSB.
> 
> gretchen

Actually according to Apple's previous spec's for the G5 Tower it is true. 
Note the last bullet below, that is 1/2 the CPU speed.

http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-G5/PowerMacG5/index.html

PowerPC G5 Microprocessor

The PowerPC G5 used in the Power Mac G5 computer has the following features:

    *  64-bit PowerPC implementation with 42-bit physical memory addressing
    *  core runs at twice the bus speed
    *  superscalar execution core supporting more than 200 in-flight
       instructions
    *  two independent double-precision floating point units
    *  Velocity Engine: 128-bit-wide vector execution unit
    *  64K L1 instruction cache, 32K L1 data cache per processor
    *  fully symmetric multiprocessing capability
    *  built-in 512 KB backside L2 cache per processor
    *  two independent, unidirectional 900 MHz to 1.25 GHz frontside buses 
       each supporting up to 8 GBps data throughput per processor

Interesting, I just took a look at the G5 iMac's and it looks as if they're 
running at 1/3 as well.  Since I can't find the spec's on the new tower,
and since the CPU seems to be that of the G5 iMac, here is what is said
about the G5 iMac CPU's FSB "two independent, unidirectional up to 600 MHz 
frontside buses supporting 4.8 GBps data throughput".

As I stated, the slower FSB speed means that the system will be slower, than
the previous single CPU 1.8Ghz model that they offered.  I for one would be
interested in seeing speed tests of the new 1.8Ghz vs. the other G5's and
some of the faster G4 systems.  In fact toss in the iMac G5's for the fun of
it.  For certain apps, the older 1.6Ghz G5 Tower is likely to outperform 
this new 1.8Ghz system.

		Zane