Advice on 68060 purchase wanted

[fishy_fiz]

As the thread title suggests, Im looking for advice on purchasing a 68060 cpu. Ideally Id like to go at least 60mhz, but Im doing the apollo1240 mod/upgrade, so I assume I wont have much success going much higher than that anyway ? I just want a system as fast as possible without any stability issues caused by trying to push the cpu too far (non towered, so Im sure that's a factor too?). If I can hit 66 or 75, then great, but Im not really looking to push it to the nth degree, so are revisions really all that important? Ive read that 60mhz and higher are manufactured on a smaller fab process (ergo newer), so I'd imagine theyre more of a safe bet for my needs/wants ? I know there's 50mhz versions using that process too, but in that case revision seems quite imporant, and Im going to need at least a 20% o/c to even hit 60mhz.

Thanks.

[Iggy]

An RC60 costs about twice what an RC50 can be had for. However, if you want at least 60Mhz I'd buy an RC60 and not worry to much about revision. You'll probably manage 66Mhz.

[alexh]

There is really only one 68060 worth buying and that is an MC68060RC50 with mask E41J.

These were the last of the 060's to be produced. They are a much lower geometry than the others meaning they clock very easily upto 90MHz.

All the RC60 and RC75 chips are AFAIK earlier chips at a higher geometry which are not quite as good. It is this E41J mask which is the important bit. As long as it has that marking it will run well.

Don't forget you need FAST memory too... 50ns SIMMs recommended.

[Damion]

Alexh is spot on. See here for more details. With the latest mask, 60MHz is fine with only a decent heatsink (watch the height). 80MHz is almost a guarantee with some additional precautions and fussing. Mine ran stable that way (stable as in crucnching RC5 for days without a hitch) for 3 years or so before I got bored and packed it away back in the closet. (I had the 1260@80, Indivision, Melody Pro, IDE-Fix Express, and a PicoPSU all in the desktop case, and it ran like a dream.)

Above 60MHz, I would consider active cooling. At 66MHz, it might seem ok casually poking around in Workbench, but after an hour or so of Quake or RC5 it will get hot.

One last edit - because the bus speed will be divided at anything above 50MHz, esoteric SIMMs are not really that essential. I tried several 60ns SIMMs, at 80MHz they all worked OK.

[Iggy]

All the recommendations regarding specific masks are quite correct, but they ignore fishy_fiz's stated goals. If all he wants is 60 or 66Mhz, why would he hunt down a processor that would sell for  a premium?
An RC60 can be had for under $90 (if you're not worried about the revision).

[golem]

Out of interest how do you go about replacing the processor on a Blizzard 1260?
Do you desolder the pins carefully from underneath and then thread through the new pins and resolder them (are the pins that long on the processor or are they seperate?). I'm much too clumsy to ever get this right by myself but I'm interested how you do it.

[alexh]

If all he wants is 60 or 66Mhz, why would he hunt down a processor that would sell for a premium?

Because some RC60's are EC meaning they don't have a working FPU. I think all RC66's & RC75's are EC and have no working FPU. They may have FPU in them, and some may have an FPU which works at 75MHz but the EC means they were sold as not having a FPU. Some are LC meaning no FPU or MMU. It is a minefield.

An RC60 can be had for under $90 (if you're not worried about the revision).

You can get an MC68060RC50 E41J for $90 if you wait a short time. Plus the peace of mind that it has both an FPU and MMU and clocks to 60MHz without heatsink or fan.

[alexh]

Out of interest how do you go about replacing the processor on a Blizzard 1260?

Desolder the 040 CPU, solder in a socket or the 060 CPU directly. Add a new ROM. Add a power regulator. Change several jumpers for power and clock frequency.

Cosmos had a entry on his blog.

http://cosmosamiga.blogspot.com/2010/02/apollo-1240-1260.html

[LoadWB]

You can get an MC68060RC50 E41J for $90

PM me with where!

if you wait a short time.

Aw, crap.  I ain't the patient type

[alexh]

This guy... but he's not selling any at the moment

http://feedback.ebay.co.uk/ws/eBayISAPI.dll?ViewFeedback2&userid=banshee121&ftab=AllFeedback&myworld=true

[Franko]

Because some RC60's are EC meaning they don't have a working FPU. I think all RC66's & RC75's are EC and have no working FPU. They may have FPU in them, and some may have an FPU which works at 75MHz but the EC means they were sold as not having a FPU. Some are LC meaning no FPU or MMU. It is a minefield.


You can get an MC68060RC50 E41J for $90 if you wait a short time. Plus the peace of mind that it has both an FPU and MMU and clocks to 60MHz without heatsink or fan.

I was about to buy some 060 66Mhz CPUs from a guy in the USA on ebay until I checked the revision and mask, seems like no 66Mhz 060 were made with FPUs and most have no MMUs either...

There's a neat site where you can find all the specs & details about all the 68K series of processors but I can't get at it right now as I'm on my old G4 and my G5 (where the link is) is currently installing OSX on a new HD that I've just installed, I'll put it here later when the G5 back up and running as it's very handy if your looking for full info if buying 060 chips...

[Iggy]

Because some RC60's are EC meaning they don't have a working FPU. I think all RC66's & RC75's are EC and have no working FPU. They may have FPU in them, and some may have an FPU which works at 75MHz but the EC means they were sold as not having a FPU. Some are LC meaning no FPU or MMU. It is a minefield.


You can get an  for $90 if you wait a short time. Plus the peace of mind that it has both an FPU and MMU and clocks to 60MHz without heatsink or fan.

I'm finding all of this fascinating as my company stopped build systems with 68K processors before the '060 came out (our last model used an '030).
If you or Franko can find some references that lists each mask by features it could prove very useful.
Right now the only one you've mentioned that I can be sure has an FPU and MMU is the MC68060RC50 E41J. But I'd also like some info on RC60, RC66, and RC75 masks.

[Franko]

I'm finding all of this fascinating as my company stopped build systems with 68K processors before the '060 came out (our last model used an '030).
If you or Franko can find some references that lists each mask by features it could prove very useful.
Right now the only one you've mentioned that I can be sure has an FPU and MMU is the MC68060RC50 E41J. But I'd also like some info on RC60, RC66, and RC75 masks.

I'll get that site for you in a wee while, unfortunately I'm waiting for my G5 to install OSX and the url is on me old HD.

It's a really handy site as it tells you which version have what and lot's of other technical specs...

[delshay]

watch out for fakes,whats printed on the outside is not always whats on the inside.

[Damion]

Quite a bit can be found with a basic search at the freescale site. There's also a decent general overview at Rudolphe's site (linked to above).