Re: Insightful read about EOL of G4? NOT!
Originally posted by Dave Marsh
Here's the link to a thoughtful analysis of the new PowerMacs:
http://www.denbeste.nu/cd_log_entries/2002/08/Anunbelievablekludge.shtml
You know, I've been reading that page, and the person writing it made some glaring common mistakes, such as:
"(I have a sneaking suspicion that they're underclocking the RAM to synchronize it with the FSB.)"
One would say that the FSB is running at 167 MHz and the DDR RAM is running at 333 MHz. However, the DDR RAM is NOT being clocked at 333 MHz, it's being clocked at the same 167 MHz as the FSB.
Since it reads both the rising and falling side of the clock pulse, it's doubling it's data throughput. Two ticks for every clock pulse.
167 X 2 = 334.
So we can see that the RAM and the FSB are running off the very same clock, at the same speed, and no synchronization is needed.
Another:
"167 MHz system bus (what is up with that? Dell's top-end systems are up to 533)"
He should have pointed out that a 533 MHz FSB is a "Quad Pumped" 133 MHz clock.
These tricks do help move data faster, but the chips are NOT running faster, just doing four times as much per clock cycle, which happens to be 133.25 MHz in this case. But they also help make the PC look faster... it's the same tricks Intel pulls with longer pipelines in the P4 so they can get the clock rate up higher... not telling anyone that their CPU is doing less instructions per cycle.
533 / 4 = 133.25
More:
"The "new" 1.25 GHz G4's aren't new. They're 1 GHz G4's which are being overclocked 25%. Apple is selecting G4's which can run that speed, and they've designed their new top-end system around them."
This is how it always works. Motorola doesn't make 800 MHz and 1 GHz chips. They make one CPU design per family, i.e., 7400, 7410, 7450, 7455, etc., and test the finished chips to see what their tolerance is, and stamp a speed on them. It's not overclocking when the chip is being run within it's tolerance rating.
I'd say the USS Clueless has its proper captain!
Listen everyone, stop believing all this FUD online. Anyone can put up a webpage and profess to be an "expert" at anything! A small amount of thinking shows they are wrong.
