ARM3 product codes

[Boydie]

What do the various ARM3 product IDs mean? I have several different ones (all VY86C020):

25FC (A5000 and one Watford ARM3 upgrade) - presumably tested to 25MHz
35PSFC (A4) - presumably tested to 35MHz, so completely wasted in an A4
PSFC (A540 and another Watford ARM3 upgrade)

What does the PSFC without a number mean in terms of speed rating?

What other codes exist?

[a1exh]

Is PSFC not describing the VLSI Technology Inc. transistor process technology?

[IanJeffray]

What does the PSFC without a number mean in terms of speed rating?

They're all clocked at 25MHz by Acorn as far as I know (lots of A5000s...)

[a1exh]

I still think it is something to do with the VTi (VLSI Technology Inc) process technology at the time. Almost all of their chips have "FC or PSFC" at the end.