I am just wondering is ALi M1249G chipset actually slows am386dx 40 to 20mhz? As i tested, in text, math, graphics programs, its not cache off or memory slow down. I dont have an oscilloscope to check it.
Chipsets don't do anything with clocking the CPU. If your 386DX40 is running at 20MHz, either your board has the wrong crystal or (more likely) some jumpers are set incorrectly.
Maybe a good idea to mention which motherboard you're using.
dionb wrote on 2024-09-25, 11:08:Chipsets don't do anything with clocking the CPU. If your 386DX40 is running at 20MHz, either your board has the wrong crystal or (more likely) some jumpers are set incorrectly.
Maybe a good idea to mention which motherboard you're using.
Seritech SER-386-AD-II.
I mean with turbo on frequency is 40mhz, with off, 20
so your question is about de-turbo speed? dont know about SER-386-AD-II but SER-386-AD-III https://theretroweb.com/motherboards/s/serite … -ser-386-ad-iii uses MX8310
Re: Clock generators on Socket 7 and older motherboards shows the pinout. You can measure pins 11 12 13 in TURBO and de-TURBO modes, if 11 goes down and 13 up then yes it is switching frequency to 20MHz. Remember clock gen frequency is double the actual CPU frequency.
btw if you can pull the board out of the case could you please upload picture of SER-386-AD-II? looks like it was a typo and OP has seritech-ser-386-ad-iii Re: Is having 386 with 486 chipset is bad?
https://github.com/raszpl/FIC-486-GAC-2-Cache-Module for AT&T Globalyst
https://github.com/raszpl/386RC-16 memory board
https://github.com/raszpl/440BX Reference Design adapted to Kicad
https://github.com/raszpl/Zenith_ZBIOS MFM-300 Monitor
rasz_pl wrote on 2024-09-25, 20:25:so your question is about de-turbo speed? dont know about SER-386-AD-II but SER-386-AD-III https://theretroweb.com/motherboards/s/serite … -ser-386-ad-iii uses MX8310
Re: Clock generators on Socket 7 and older motherboards shows the pinout. You can measure pins 11 12 13 in TURBO and de-TURBO modes, if 11 goes down and 13 up then yes it is switching frequency to 20MHz. Remember clock gen frequency is double the actual CPU frequency.
btw if you can pull the board out of the case could you please upload picture of SER-386-AD-II?looks like it was a typo and OP has seritech-ser-386-ad-iii Re: Is having 386 with 486 chipset is bad?
Yeah, sorry for typo. I cant access its clock generator now (as there is no cable managment and its filled with wires), i think its really downs mhz (why pccheck shows me 39 mhz with and without turbo??)
