http://wiki.icomp.de/wiki/ACA1232#50MHz_limited_edition
Does your card have the new SD-Ram controller? If not, then you can not pass it off as one of those rare 50MHz versions that were available from November 2015. I'm just being honest here, this is not an attack upon you, but I don't think it's fair to try and pass your card off as one of those rare versions, people need to know exactly what they are buying.
Noooo. Original made in 2015 50 MHz ACA1232 RAM controller work on 50 MHz, oscillator 50 MHz. CPU work on 50 MHz.
All ACA1232 20, 25, 30, 33, 40 MHz card PCB same. The difference CPU freq (in 33 MHz card are 33 MHz CPU), and R1-4 resistors only. But original 1232 50 MHz RAM controller different. Original 1232 25 MHz card freq. multiplier resistor R2 (RAM 50 MHz, CPU 25 MHz), original 50 MHz card R2 (RAM 50 MHz, CPU 50 MHz).
My 1232 RAM clock 100 MHz, look this topic message 1:
R1-4 switch configuration, original not modified oscillator 20 MHz, multiplication, not divide.
All off, RAM 2× = 40 MHz, CPU 20 MHz.
R2 on, RAM 2,5× = 50 MHz, CPU 25 MHz.
R3 on, RAM 3× = 60 MHz, CPU 30 MHz.
R1 on, RAM 3,33× = 66 MHz, CPU 33 MHz.
R2+4 on, RAM 4× = 80 MHz, CPU 40 MHz.
R1+4 on, RAM 5× = 100 MHz, CPU 50 MHz.
R4 on, RAM 5,33× = 106,6 MHz, CPU 53,3 MHz.
Never try!R2+3 on, RAM 6× = 120 MHz, CPU 60 MHz.
Never try!R1+3 on, RAM 8× = 160 Mhz, CPU 80 MHz.
Never try!Never try other 7 combinations (R1+2 on, etc.)!Look:
http://wiki.icomp.de/wiki/ACA1232#ACA_12xx_BenchmarksOriginal 50 MHz 1232 dhrystones 10576, my 1232 11478. The reason of the difference RAM speed!
The ACA1233 55 MHz oscillator 55,55 Mhz, RAM and CPU work on 55 MHz.
ACA1233 40 MHz oscillator 80 MHz, RAM work on 80 MHz, CPU work on 40 MHz. Divide 1/2 = RAM controller, not resistors!
New 1233n 26 and 40 MHz oscillators 80 MHz. At both version RAM work on 80 MHz, CPU work on 80/2=40 MHz, or 80/3=26 MHz. Simple.
Divide 1/2, or 1/3 = RAM controller, not resistors!
There was need for a new RAM controller (ACA1233-55, and 1232-50), because the RAM chips are not work on 105-110 MHz. (ACA1233-55 CPU freq. 55 MHz, RAM freq. 110 MHz, this not work.)
100 MHz are big loads already (1232-50). They (icomp) did not want to use the RAM chips on approximately 95% load.
ACA card RAM chips: EM63A165TS-6G.
http://www.etron.com/manager/uploads/EM63A165TS_v1.4.pdf166 MHz Fully synchronous operation.
100-110 MHz why not OK?
R4 on, RAM 5,33× =
106,6 MHz, CPU 53,3 MHz.
Not stable, start disk pic OK, but boot = guru.
They used new RAM controller for the 1232-50, if a new controller was needed for the 1233-55.
1233-55 limited edition:
http://wiki.icomp.de/wiki/ACA1233#55.55_MHz_limited_edition