It's equivalent.
The 1Ghz Aluminum PowerBooks (at least the 15 and 17") have L3 cache. They are the only models of the Aluminum series that do.
I know. I have a 17" AlBook with L3 cache.
The difference has to be the G4 chip I think.
Aside from CPU, the only other hardware differences to come to mind, and most pertinent to the first, second, and third parts of the Geekbench test, would be, respectively, the speed of the GPU and the speed of the memory in the aluminium 1GHz.
For the latter, the memory speed boost in the aluminium 1GHz would offset whatever boost having an L3 cache plays in the titanium 1GHz: the jump from 144-pin PC133 (133Mhz) to 200-pin PC-2700 at 333MHz was a substantial speed bump on the memory bus, partly making up for what the CPU itself lost in the aluminium iteration.
As for the GPU, the clock speeds of the Radeon Mobility 9000s ranged between 250 and 275MHz (depending on the revision, I think 250MHz for Radeon Mobility), while the Mobility Radeon 9600s, as memory serves, ranged between 325MHz and 500MHz (depending on the revision, I think 325MHz for the Radeon Mobility).
Even Everymac finds the Geekbench scores they posted being fairly comparable —
[1] [2] — despite one being a “pear-lemon” combo and the other being, well, an “apple-lime” combo, to borrow from produce.
One way I
could envision the GB scores here being so different might be from using the same install drive in both machines, as opposed to using installations specific to each machine using the same Tiger DVD install (i.e., allowing system installation to configure for specific hardware), but offhand I’m not sure how the installation itself might vary.