[lothar56]

I have a Sonnet G4/400 M1 ZIF card. When the stock jumper setttings are used, it runs at 400MHz. But when I switch up the jumper settings according to this table, the clock speed does change, but not to what the table specifies. If I put it on the "83MHz 33MHz 416MHz x5" setting, the bus speed runs at 83MHz like it says, but the processor runs at 333MHz. I've heard that these can't be overclocked, but it's obvious that the speeds can be changed. I did have it running at 420MHz a while ago, but I don't know what jumper settings I was using, something in the 300MHz range I think. Anyone have any ideas?

[lothar56]

For anyone who's interested, it seems the processor speed depends on the bus speed, but I'm still not exactly sure how. When I set the bus to 75, it runs at 450 (x6), and it's the same with 70 and 420. If the bus is at 83 though, the processor drops to 333 (x4). So that's what I found.

[bradoesch]

You've pretty much got it figured out.

Processor speed = (Bus speed) * (Multiplier)

[lothar56]

The tricky part is that the upgrade card changed the multiplier so I couldn't rely on any of the jumper tables I had. Hopefully this info will be useful to someone somewhere.