Cosmos' 105MHz Apollo

[wXR]

Just saw this in my feed. Wow.

http://www.youtube.com/watch?v=Pqefb...=youtube_gdata

[roy bates]

i was going to try this out but i cant find any oscilators between 100 and 110mhz.

[Zetr0]

@roy

You can get variable ones my friend, OR use a clock multiply / divisor IC, or build your own from an F74 (or two)

while 105 is a bit of a holy grail - Its only 5% more of 132 MIPS - 6.6 MIPS more... and when you are rocking a solid / stable 132 MIPS.... seems pointless to go up any more.

Now.... 110 MHz .... well now thats totally different!

[roy bates]

Originally Posted by Zetr0

@roy

You can get variable ones my friend, OR use a clock multiply / divisor IC, or build your own from an F74 (or two)

while 105 is a bit of a holy grail - Its only 5% more of 132 MIPS - 6.6 MIPS more... and when you are rocking a solid / stable 132 MIPS.... seems pointless to go up any more.

Now.... 110 MHz .... well now thats totally different!

ive found a part for a variable oscilator havent tried it yet though,

your right by the way i dont really need 105mhz,its just to see if it will you know how it is mine wont go to 110mhz ive tried that one.


EDIT: for me it would be to see how the mmu and fpu handles really more than anything.

[Zetr0]

indeed, the MMU / FPU is the weak part of the circuit

[johnim]

i just wished blizzards could go that high :

[roy bates]

Originally Posted by johnim

i just wished blizzards could go that high :

im pretty sure a blizzard can do 80-90mhz with 50ns ram and a revision 6,which is pretty damn fast.

[johnim]

now have you a spare rev 6 and could you update it roy.

[roy bates]

Originally Posted by johnim

now have you a spare rev 6 and could you update it roy.

i'll have a look in my parts box a bit later,im sure ive got a spare somewhere i cant promise anything though.(because i cant remember where i left it)

ive definitly got two 72 pin 64mb 50ns simms.

the only problem is your scsi wont work at these speeds.

[Zetr0]

it is a pity the SCSI controller cannot be fed an Async clock.

[stachu100]

Originally Posted by roy bates

im pretty sure a blizzard can do 80-90mhz with 50ns ram and a revision 6,which is pretty damn fast.

You are right:
https://www.youtube.com/watch?v=0UsZ...e_gdata_player

The trick is that 060 rev6 will work up to 110MHz on Blizzard 1260, but Blizzard memory controller is not working any more.
Most of the Blizzard 1260 cards will work with 106MHz clock, but FAST is not visible - even 40ns modules.
Usually 75MHz is the max for Blizzard for normal operation with FAST.
This one from link above was an exception.

[johnim]

my board is a dce 1240/1260 and is not socketed which was from new in 99 cost me £300 which i origionally had a 1240 which was £150 and sent back to be upgraded

so what is the fastest with scsi and ram working

and also fastest with just ram

[Zetr0]

@John,

As Statchu has pointed out, the most common limit to a Blizzard 1260 is 75Mhz with FAST RAM. you wont get SCSI past 66Mhz -

I am unsure but I also believe that this will negate the use of the extra ram on the SCSI controller as well.

As Statchu points out, while you can get fast on the Blizzy, you wont gain anything as you dont have any fast RAM access

[johnim]

ok thanks keith so looking at 75 then with ram to be worth it

cheers

[Zetr0]

that really comes down to what you need my friend,

I would be happier with Fast SCSI II DMA and 256MB of ram at 66Mhz (approximately 86 MIPS)

compared to just 128MB RAM and 98 MIPS ( only 12 MIPs difference, but you lose FAST DMA SCSI II and 128MB of RAM

[roy bates]

if you want the scsi as well,you might get lucky and run both at 66-72mhz at a push if your lucky.

but at these speeds you wont really need a revision 6 a revision 5 will do.(ive clocked revision 5 to 70-72mhz and be stable)

as zetro has said,it all boils down to what you want really.


i had a blizzard years ago and fitted it with a revision 5 and it was only stable at 70mhz with scsi,and i thought i only got lucky there with mine.

[johnim]

ooh roy would you be able to try mine but any speed increase will do with what ive got now a fan on top will help too. its in my tower. do you have xtals if not can you sort some out and give us a price for all the work. cheers


if you have time that is

[roy bates]

if i find all the parts i'll do it for free.

[wXR]

Originally Posted by roy bates

im pretty sure a blizzard can do 80-90mhz with 50ns ram and a revision 6,which is pretty damn fast.

Apparently Cosmos managed to find 40ns RAM...

http://leblogdecosmos.blogspot.com/2...imms-40ns.html

God knows how he pays for all of this and has so much time to dedicate to the hobby, but it's really cool to go through his blog!

[wXR]

Originally Posted by stachu100

You are right:
https://www.youtube.com/watch?v=0UsZ...e_gdata_player

The trick is that 060 rev6 will work up to 110MHz on Blizzard 1260, but Blizzard memory controller is not working any more.
Most of the Blizzard 1260 cards will work with 106MHz clock, but FAST is not visible - even 40ns modules.
Usually 75MHz is the max for Blizzard for normal operation with FAST.
This one from link above was an exception.

stachu is this also true of the blizzardPPC cards?

how about cybervision?

[stachu100]

I only tried 060@72MHz max on BPPC.

[wXR]

Out of fear of destroying the card/chip, or just no interest in pushing it further?

[stachu100]

Both I would say.