I've picked up an old Powerbook 1400 from eBay, for £65. It's missing a floppy drive / CD-ROM drive, so it's going to be a bit of a challenge getting data in and out of it. I think perhaps at my Dad's house there's a HDI-30 to SCSI converter, but failing that, I can use AppleTalk between my Performa 400 and the Powerbook 1400 or maybe simple serial transfer.
The PowerBook 1400 in question is the PowerPC 603e, 117MHz model without a level 2 cache. So, it's slow. But how slow, is the big question. I tried to find out from LowEndMac. It gave the performance as
"Performance: 114/137/152 (117/133/166 MHz), MacBench 4 (also 42,076 (117 MHz) Whetstones)"
But when I tried to compare it with other Macs of the era on LowEndMac, particularly the Performa 5200, they all provided benchmarks for different test suites. The 6100/60 was given relative to MacBench 5, MacBench 2 and Speedometer 4. Performa 5200 was just xxx relative to a Mac SE. And so forth.
However, a little while later I came across this reddit page:
And it gave a screenshot of a bunch of early PowerPC Macs (and a Quadra 630) benchmarks for MacBench 4!!! Here's the data as a simple table: