check out the applestore -- they have fast machines for sale now.
what the heck are you doing that the powermacs can't handle?
i regularly record 8 simultaneous tracks of full-bandwidth audio on my 3 year old dual 500. it flies.
what are YOU doing that's so intensive?
fullbandwidth ?
44.1Khz, 24bit, 48Khz, 24bit or 96Khz 24bit ?
Stereo or mono ?
I can record 32 simulataneous tracks at 48Khz, 24bit on my 5 year old beige G3, it doesn't mean I can use many plug-ins or software synths with it, even an 800MHz G4 is only around 3 times faster for purely audio and plug-ins.
Software synths are another thing entirely, Altivec plays a large part in their performance and cpu overhead but for raw plug-in performance an Athlon 2200XP or a 2Ghz or more Pentium 4 Northwood running on a TRUE DDR system bus is up to 3 times faster comparing single cpu to single cpu performance in protools LE.
Imagine how useless a 1.8Ghz G4 will be in realworld terms.
A 1.7Ghz Pentium 4 with a PC133 SDRAM chipset was actually around 10% slower than a 1 Ghz Pentium 3 with PC133 SDRAM. Sure there was the little matter of anaemic cache sizes, bloated pipelines and a host of other inefficiencies in the name of clockspeed on the Pentium 4 compared with the Pentium 3 but all the same, PC133 SDRAM on a 1Ghz chip isn't as bad as PC133 on a 1.8Ghz chip no matter how efficient the chip might be.
Baring in mind 133Mhz = 133.333 and 167Mhz = 166.666, Here's the cpu on a 1Ghz Quicksliver G4 :
CPU (s) : 1000Mhz
L1 : 32K + 32K 1000Mhz SRAM
L2 : 256K 1000Mhz SRAM
L3 : 2Mb 250Mhz DDR SRAM (1 quarter cpu speed, double pumped to 500Mhz)
Bus Speed : 133Mhz (cpu speed / 7.5)
System RAM : PC133
Now the 1.25Ghz G4
CPU (s) : 1250Mhz
L1 : 32K + 32K 1250Mhz SRAM
L2 : 256K 1250 Mhz SRAM
L3 : 2Mb 312.5 Mhz DDR SRAM (1 quarter cpu speed, double pumped to 625Mhz)
Bus Speed : 167Mhz (cpu speed / 7.5)
System RAM : 333Mhz DDR SDRAM (irrelevant because the cpus don't benefit from the extra bandwidth)
That's an equal bottleneck to a 2Ghz Pentium 4 running on a chipset supporting 266Mhz DDR SDRAM, except the mac is half the clockspeed and has the large L3 cache to act as a buffer to the relatively slow system RAM.
In basic terms for either the 1Ghz QS G4, 1.25Ghz Mirror Doors G4 or 2Ghz Pentium 4 on a DDR chipset, the cpu is being fed 2 15ths of the bandwidth it really needs from main system memory across the system bus.
Now for the 1.833Ghz G4.
1.833Ghz isn't possible on a 133Mhz bus so that would make it a 167Mhz bus like the 1 and 1.25Ghz G4 in the mirrored doors G4.
From the specs in the article and from previous specs of the G4s and apple's system controller here's how it would stack up :
CPU (s) : 1833.3Mhz
L1 : 32K + 32K 1833.3Mhz SRAM
L2 : 512K 1833.3 Mhz SRAM
L3 : 2Mb 458.3 Mhz DDR SRAM (1 quarter cpu speed, double pumped to 916.6 Mhz)
Bus Speed : 167Mhz (cpu speed / 11)
System RAM : 333Mhz DDR SDRAM (irrelevant because the cpus don't benefit from the extra bandwidth)
So a 1.8Ghz G4 will only be able to feel 1 11th of the bandwidth the cpu needs because the cpu still doesn't support a DDR system bus.
The bus speed isn't going to be anywhere near fast enough to feed enough to the cpu for it to perform efficiently unless 333Mhz DDR SDRAM can interface directly with the cpu. It's still going to have the same bottleneck the G4s have had since their introduction, a bottleneck that's really holding the cpu back from achieving it's true potential.
