View Full Version : A4000D csppc 68k@50 and 80 MHZ - via turboswitch... (100MHz coming soon...)

27th January 2015, 19:47


I will post details, documentation and the 100MHz this evening, i guess... :)

Edit: just arrived at 90MHz.... here are the first screenshots:



extra cooling for the cpld-chips (there is more necessary, i guess):


27th January 2015, 19:56
AWESOME!!! How did you do this??

27th January 2015, 20:22
So all I ever needed to double the speed was a simple turboswitch? :)

27th January 2015, 20:26
yup...costs a buck fifty...TOPS ;)

Think people are waiting for a full walkthrough by holzroller!...I am...not that I ever would violate my CSPPC, but knowledge is power!

27th January 2015, 22:50
What 3.9 install is this?

28th January 2015, 00:18
its OS 3.9 and the amistart taskbar...

hmm, the 100MHz -crystal seems to want some trouble with me... i will look tomorrow what happens here.... some early pics of the journey to this you will finde here:
an here:
btw i will post a documentation here this week...

28th January 2015, 00:51
No permission for the site :(

Der Zutritt zu dieser Seite ist Ihnen leider verwehrt. Sie besitzen nicht die notwendigen Zugriffsrechte, um diese Seite aufrufen zu knnen.

1st February 2015, 00:35
I need to get another 100MHz crystal. the one i have here seems not to fit as i planned. Meanwhile i have found a solution to solder a crystal-socket for the third oscillator without blocking the first RAM-Bank of the csppc-board.

actually my soldering station is defective, im waiting for the new one. until i got this and the new 100MHz crystal there are "only" 80MHz possible. As kronuz suggested, maybe some of you would like to know some details of my project...

so here we go: because of the linked Amiga-dresden-page needs to register for learning more, i will publish some details of my journey here and now... Lets go:

the case/cooling:

hmm, as you know, the a4000d is a desktop-case and there are a few opportunities for cooling. This means, i i had to enhance the airflow inside the case:
82527 82528 82529 82530

as you can see, there is a mounted a fan at the front of the case. this one is blowing fresh air into the case directly over the cpu-board.


One radial-fan sucks fresh air through a slot-plate mounted on the left rear upside the external vga-connector of the cvppc (1). Another radial-fan blows the hot air out of the case, mounted upside the parallel-port right of the daughterboard (2). A third radial-fan (3 - not mounted at this pic) leads the fresh air from the left case-area into the right area - with help of the front-fan directly over the cpu-board. The psu itself sucks air out from the case too...

Now some details abaout the cpu-board. i have mounted one of stachu100s freescale 68060R60 - cpu. to run this cpu at more than 72MHz, i had to solder the significant oscillator next to the 50MHz Oszillator, which comes originally with the board. mounted here, the actually 80MHz oscillator clocks the CPU separately from other devices like scsi-bus.


But you have to pay attention for the RAM-Modules: as you know, you can change the csppc memory-speed by selecting 60ns or 70ns inside the ppc-menu. If the 80MHz oscillator is mounted and activated, the Ram would be accessed with 37.5ns (at 60ns setting) and with 43.75ns (when 70ns is selected via the scppc-RAM-menu). So you need fast SIMMS! With 70ns , my 60ns 32MB SIMMS are working great - setting RAM-speed to 60ns the machine does not boot. it was clear, these modules will not allow to push the 100MHz. it took me 4 months and a lot of mail-communication, but finally i got some perfect NOS 32MB SIMM, 50ns timed.


Next step: soldering the "Turbo-Switch". for allowing switching between the standard 50MHz-Osicllator and the soldered 80MHz one i had to remove the corresponding jumper and to solder the connectors for the switch.


thats it... :)

at the end, some screenshots after running busspeedtest, sysspeed and sysinfo benchmarks...

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1st February 2015, 00:36
82544 82545 82546

a short clip showing switching between 50 and 80MHz while running warp3d 68k demo comes this sunday...

1st February 2015, 17:57
Excellent work there holzroller and a good how to :thumbsup:

1st February 2015, 18:36
I see you use 3 crystals, so you keep the main bus at 50mhz?

Whilst it's pretty cool, it's a risky experiment with an expensive card!

1st February 2015, 19:20
You are right, i kept the 50Mhz System-Speed-Chrystal. I know, changing it against a 60Mhz or 66Mhz one would speedup the whole system too. I've been thought about this a long time. Finally i think, running the 68k at 100Mhz and also clocking the systembus at 66mhz could stress the boards elektronic too much. In addition i plan to send the board to stachu100 for upgrading the ppc-part. The card with 66Mhz systembus, 100Mhz 68k and 350+Mhz ppc would be too much i think... ☺

1st February 2015, 23:47
My first csppc was overclocked on the bus to 66mhz and was unstable. Eventually the cpld cooked it's self even though I reduced the clock to 55mhz it was too late and eventually died so please don't try that. Maybe with some cooling it would be OK, I know cosmos has put heatsinks on csmkiii clocked at 66mhz but I think better keep it safe.

Faster 060 isn't really needed when you ppc.

3rd February 2015, 17:01
i agree and i will not try this.it is risky to operate the bus with 60 or more MHz. however - cooling is the most important thing here. especially you have to take care for the cpld. This is the reason for my complex fan-layout here. air pressure left from the daoughterbord and air underpressure right from the daughterboard. a sealed housing an only one location for air pressure equalization: the gap between the daughteboard and the front of the case. the fan in front of the csppc-board directs the airflow in the direction required. Of course the 68k and the cvision-chip got thair own heatsinks and fans...

BTW: you really feel the 80Mhz while internet-browsing, icon displaying. AmiVNC also gets a little boost while accessing the Amiga remote via UltraVNC (im still looking for a ppc based vnc-server for OS3.9... (possibly you know anyone? :) ). And the amistart menu-popups are responding much faster. anyway all feels more *smooth*... :)

BTW: do you or anyone else know an "instant" cpu-Benchmark (OS3.x) wich shows the CPU-Power live?

3rd February 2015, 21:22
Im still waiting for my soldering-station. Meanwhile i decided to make another clip, running some Benchmarks @80MHz... So, have fun!! (any comment is welcome of course...)


24th February 2015, 00:05
Well, ive got my new soldering-station. And also a nice oscilloscope.... And - i recieved some fitting oscillators... :)

The 100+ MHz - project can start... lets go... (thread will be updated within 2 or 3 days, i hope... :)



25th February 2015, 22:24
reached 90MHz (look at the first post!) :)

25th February 2015, 22:40