You guys are forgetting how important the L3 cache is. Yes, the P4 can have an increddible 533mhz fsb, but it is still dependant entirely upon that bus to get data, whereas the G4's L3 cache is on a separate direct bus to the chip. (each chip has it's own L3 bus in the case of the Dual 1ghz)
"The L3 cache boosts processor function by providing fast access to data and application code at speeds of up to 4 gigabytes per second (GBps). And the L3 cache is even more effective at speeding up processing because it has a dedicated bus to the G4 chip, making the full 4GBps data throughput always available unimpeded by bottlenecks caused by other data (unlike Pentium 4-based systems, which dont have L3 cache a disadvantage that leads to congestion between various data streams, and slowdowns in the overall rate of data transfer). "
So you have 4GB/s for each of the 2mb caches (per chip).
"The high speed L3 cache with its dedicated bus enables the PowerPC G4 processor to receive data up to five times faster than it could from main memory... so it isnt idling while waiting for the next task to arrive. "
Everyone is talking about how the G4 is starved for data all the time because of SDR RAM, but you have to remember that the main memory bus isn't the only place data comes from.
"The L3 cache is large enough to store active application code and data. When you run an application, most of the active code for the program along with most of the data being used is in L3 cache. "
I'm not sure how small each data chunk usually is, but I don't think many are larger than 2mb. Anyone know about this? Aren't larger chunks broken down most of the time?
I personally will be happy to see DDR memory come to the PowerMac line, if anything, just to satisfy all you morons out there, but I don't think the gains will be as much as many here have been expecting. I'm pretty confident that the G4 isn't as starved for data as so many of you seem to think.
I feel a flame post coming on...