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Apple Ships Dual 1.25 GHz Power Mac G4
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Jules
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#1
20th September 2002
Old 20th September 2002
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Apple Ships Dual 1.25 GHz Power Mac G4

Apple Ships Dual 1.25 GHz Power Mac G4





CUPERTINO, Calif., Sept. 18 /PRNewswire-FirstCall/ --
Apple(R) (Nasdaq: AAPL) today announced it has begun shipping the
Power Mac(R) G4 with dual 1.25 GHz PowerPC G4 processors, the fastest
Macintosh(R) ever for creative professionals. The dual 1.25 GHz system has a
new Xserve(TM) high-performance architecture with support for up to 2GB of
Double Data Rate (DDR) memory at up to 333 MHz, the industry's first ATI
Radeon 9000 Pro graphics card and an enhanced enclosure with increased storage
up to nearly half a terabyte.
"The Power Mac G4 with dual processors running at 1.25 GHz is the fastest
Mac ever made," said Philip Schiller, Apple's senior vice president of
Worldwide Product Marketing. "The combination of the Xserve architecture and
Mac OS X version 10.2 'Jaguar' provides an incredibly powerful and stable
platform for our professional customers."
The new all dual-processor Power Mac G4 line also ships with Apple's new
Mac(R) OS X version 10.2 "Jaguar" pre-installed, offering more than
150 amazing new features and applications. Taking advantage of "Jaguar's"
advanced UNIX-based architecture and symmetric multiprocessing capabilities,
the Power Mac G4 delivers over 18 gigaflops (18 billion floating point
operations per second). In application testing*, the dual 1.25 GHz Power Mac
G4 performs image editing tasks up to 90 percent faster, MPEG-2 video encoding
up to 43 percent faster, and scientific analysis up to 440 percent faster than
a 2.53 GHz Pentium 4-based PC.
The dual 1.25-GHz processor Power Mac G4 is available now through the
online Apple Store(R) (http://www.apple.com), at Apple Retail Stores and through
Apple Authorized Resellers for a suggested retail price of $3,299 (US) and
includes:

-- 2MB of DDR SRAM L3 cache per processor with up to 4.6GBps throughput;
-- 512MB of DDR SDRAM memory at up to 333 MHz;
-- a ATI Radeon 9000 Pro graphics card with 64MB DDR SDRAM in 4x AGP slot;
-- a 120GB Ultra ATA/100 7200 rpm hard disk drive; and
-- a SuperDrive(TM) DVD-R/CD-RW optical drive.

*Performance tests were based on commonly used operations in Adobe
Photoshop 7.0, MPEG-2 encoding using iDVD 2 software and Sonic DVDit
Professional Edition and the Ligos encoder, and A/G BLAST and NCBI BLAST
software.
#2
20th September 2002
Old 20th September 2002
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I found this to be a fascinating look at the new DDR ram based Macs vs the up-till-now SDR based Macs:

http://www.barefeats.com/pentium4.html


A couple of things, if you please. First, this is a Mac oriented site. Secondly, yes these are G4 vs P4 vs Athlon based benchmarks, but the point of interest is the standard G4 vs the XServe at 1GHz. That is basically DDR vs SDR, in the main.

Bottom line, really, is that DDR in the new Macs is all about marketing, none about performance. Why? Because on the PC side, systems using DDR also have the equivalent of a DDR based Front Side Bus. It's xfering data at double (or for the P4 and Rambus x4) of the actual FSB clock speed.

For whatever reason, this has not happened with the new DDR based Macs, and the FSB is still 133 or 166MHz. The DDR ram is quoted in the Apple press release as being 333MHz. Correct. Unfortunately, it sits around waiting for the half as fast FSB, to little useful effect.

The net result, as you can see in the independent benchmarks, is that the XServe with DDR is no faster than the (old) G4 with SDR. A little slower here and there, actually, since latency is also a factor. FSB on both of these boxes is 133MHz as opposed to the 1.25GHz, which is 166MHz.That should help the 1.25 a bit more.

And though it's not the real issue in this thread, the benchmarks also show two other things. First, why AMD has so many fans on the PC side. Second, Apple obviously carefully cherry picks which Photoshop tests they use in order to be "90% faster".

On a related topic, it does appear that IBM and their new "GigaProcessor Ultralite (GPUL)" is the frontrunner for the next generation Macs. It's a 64 bit CPU. No idea of a timetable yet. It appears the G5 may not happen, or in any event, happen soon enough.

Regards,
Brian T
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20th September 2002
Old 20th September 2002
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21st September 2002
Old 21st September 2002
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some points to consider

Quote:
Bottom line, really, is that DDR in the new Macs is all about marketing, none about performance. Why? Because on the PC side, systems using DDR also have the equivalent of a DDR based Front Side Bus. It's xfering data at double (or for the P4 and Rambus x4) of the actual FSB clock speed.
I wouldn't call it all "marketing" DDR does have some benefits and I'll explain why.

Yes the Processor to Memory bus is limited to 1.3GBps. That is going to affect the speed in some areas. However Apple was right to add DDR. Here's why



Note the Dual G4's at the top of the pic. The connection you see there from the Procs to the System Controller is 1.3GBps Maximum. However AFTER the System Controller it's 2.6GBS(DDR). You can clearly see that AGP, PCI,RAM, ATA-100 Controller, and the ATA-66 Controller all connect to this System Controller at 2.6GBps.

The next logical question would be "Doesn't ALL data have to flow through the FSB?" and Apple neatly answers that on the Powermac page here



Memory Enhancements

Quote:
The resulting throughput between main memory and the system controller is up to 2.7GBps, more than double the throughput from the previous dual 1GHz Power Mac G4. DDR SDRAM also increases systemwide memory bandwidth to the processors and all other elements of the system. At the same time, direct memory access allows system elements, such as a hard drive controller or a graphics processing unit, to send and receive data directly from main memory, without going through the processors. The added bandwidth allows system elements to function independently at high data rates, boosting total system performance.
So how will this manifest itself in benchmarks? Most likely it won't. Barefeats tested throughput and speed of ONE application but a design like you see above is Apple getting things like the Gigabit Ethernet, Firewire and ATA-100(which supports 48bit addressing so you CAN use Drives over 137GB BTW) off the slower memory bus of previous Macs and utilizing the 2.6GBps of DDR.

The only real way you could test for this is to run multiple apps/benchmarks simultaneously and look for which computer handles itself best under full load. I think you would find the DDR Macs to be superior in this regard. And quite honestly when we're asking our Macs to run multiple Audio apps simultaneously we're doing just that.

Concerning DDR and FSB. There is a misconception that having a full DDR bus will "unlock" the speed of the G4. While it will undoubtedly help we should not expect huge increases in speed with the addition of "just" a DDR FSB simply because with only 7 Pipline stages the current G4 just doesn't suffer enough of a "hit" by having a branch misprediction. Intel P4's have 20 Pipelines so if there is a misprediction it has an additional 13cycles to obtain the correct data. Hence the need to have FAST memory to retrieve the data as quickly as possible while the processor stalls.




Quote:
On a related topic, it does appear that IBM and their new "GigaProcessor Ultralite (GPUL)" is the frontrunner for the next generation Macs. It's a 64 bit CPU. No idea of a timetable yet. It appears the G5 may not happen, or in any event, happen soon enough.
Heeh Brian you're on top of things as usual!

Here's a link for all interested. How's this for drool worthiness. A GPUL 64bit proc should be twice as fast clock for clock over todays G4. Here's the kicker. It's likely to be a dual core. Yes that means Dually Performance in one chip and that means that we're talking a 4X improvement for Dual Core 2Ghz!!!

http://www.eweek.com/article2/0,3959,543317,00.asp
#5
21st September 2002
Old 21st September 2002
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Thanks for the education on the Mac bus topology. I do try and follow tech developments across platforms. You never know when one is going to finally gain a clear and objective advantage.

This IBM CPU looks pretty serious, but as usual, it's all about timing. If Moto had been able to get the G4 up to 1GHz a good bit sooner, the whole horsepower picture would have been reversed.

If they can make this thing real in the next year, Mac users will be gratified in the extreme, I would guess. Heck, I'll probably be one myself at that point, should it happen.

Since we're now in uber-geek mode anyway, I'll forge ahead a bit more. DDR under a single rate FSB may help the Mac a bit here and there, but it's definitely hobbled nonetheless.

Here's a pretty interesting link to a comparison of a number of different chipsets in use with the same speed P4 using identical components.

http://www.tomshardware.com/mainboar...gl_performance

Check the Intel 845 and 845D specifically. Same chipset, one with SDR and the "D" with DDR and the attendant double rate FSB. Otherwise identical. There is not a single benchmark where DDR fails to show an advantage, as opposed to the Mac DDR vs SDR, where the advantage is spotty. So I suppose we both get to be correct here. There is some advantage to DDR for the new Macs, but in a good many cases it ranges from slight to none, due to the FSB issue, IMO.

One question. The Mac article you quote mentions Direct Memory Access as though it were somewhat new. How long have Macs used DMA to address IDE drives?


Regards,
Brian T
#6
21st September 2002
Old 21st September 2002
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I just did some snooping around. Looks like they are in fact aiming at about a year from now for release of the IBM CPU. I would guess that means a year from Christmas as about the best case scenario to see this in a Mac you could actually buy.

Not time to hold our breath yet it seems. I would guess at 18 months.


Regards,
Brian T
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21st September 2002
Old 21st September 2002
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DMA. You know I don't know when they added DMA to the ATA bus.

I guess i'm just trying to temper my enthusiasm for a full DDR bus because I think that it will be beneficial but I doubt we see much larger than a 10% increase in memory bound processes.

LOL..18 months sounds about what the Apple calendar calls a year e.

Well Apple is going to have to hold on tight because Intel and AMD are preparing to launch their sprints next year. AMD knows Hammer is their hope for keeping up.

On a off topic mode.

I recently found out that Apple has hired Dominic Giampaolo and Pavel Cisler of BeOS fame. Dom basically wrote BFS(Beos File System) and added Journaling in like 1200 lines of code!!! Of course he didn't have legacy issues to deal with but my limited experience with BeOS was nice. Instant searches....you could unplug the computer and wouldn't lose any data nor have to run a Disc Check.

If Apple is smart they'll be revamping the FS in OSX using his handy work. Imagine you have Audio files and sample littered all over 300+ Gigabytes of HD. Good luck finding them unless you're a very organized individual. Hopefully we'll see OSX someday with a Journaling FS with Database like functionality in the FS as well as great Metadata(like the OS9 Type/Creator features but better with no need for .xxx extensions).

Sorry for that rant but it does apply to all of us. let's hope our Hardware is worthy of running such an OS.
#8
22nd September 2002
Old 22nd September 2002
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Quote:
Originally posted by hmurchison
DMA. You know I don't know when they added DMA to the ATA bus.

Yeah, it's funny. I always thought IDE on the Mac had such a bad rep on the Mac early on because of the lack of DMA. Man, on a PC, turning DMA off is death for a DAW.

It's wild that all the Firewire HDs being run now are simply IDE drives in a Firewire case. I guess everybody knows that, right?


Regards,
Brian T
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