Benchmarks 71B versus 48GX

[KimH]

Actually, the later 71B has the refreshed 1LK7 CPU.

According to legend HP always wanted the chip to run a 1MHz Clock, but something went wrong and they ended up with 650KHz which is the 1LF2.

In later years - i think mid 86, they started to mount the 1LK7 on the PCB.

There is no way - that I know - to see the actual CPU version without opening the Case.

If it is 1LK7, the LC circuit can be modified to run at about 1MHz - at about 1.1MHz the CPU starts to become unreliable.

/KimH

(05-03-2014 01:57 AM)Mark Hardman Wrote:  

(05-02-2014 09:23 PM)John W Kercheval Wrote:  Does anyone have a raw chip speed comparison between the 71B and the 48GX?

From Craig Finseth's invaluable HPDATAbase:

HP-71
Saturn, 4-bit, 640 KHz 1LK7 5 V CMOSC

HP-28C
1LK7 Saturn CPU (1 MHz)

HP-28S
Lewis, 1 MHz

HP-48SX
Clarke (147 pin TAB), 2 MHz

HP-48GX
Yorke (00048-80063, 160 pin QFP), 4 MHz

Mark Hardman