[johnnym]

Not sure if this fits in here, but:

If you have different processor modules (PM) for your Octane(2)s you might notice mechanical differences in their heatsinks. E.g. for my collection all R10000 based PMs (incl. dual PMs) use a machined heastsink made out of an extruded aluminium piece, whereas all R12000 PMs (also incl. dual PMs) use a machined heastsink out of a cast aluminium part.

Examples showing:

• Dual R10000 PM from https://hardware.majix.org/computers/sgi...08.big.jpg
  
  
  
• Dual R12000 PM from https://bukosek.si/hardware/collection/s..._front.jpg
  
  

My question now is, is that true for all PMs out there?

I.e. if it has an extruded heatsink it's a R10000 based PM and if it has a cast aluminium heatsink it's a R12000 based PM.

[weblacky]

My brain chocks this up to just supplier and production run.  SGI didn't make 1 million of each system. They had a dedicated production run for every PCB revision, I assume.

They sourced the parts they could, and you might expect there to be differences between generations of each production. At most a heatsink is a heatsink as long as it meets the basic requirements under testing. if your question is, could you swap the heatsinks and everyone would be OK, I would suggest no, but that could be for a myriad of reasons, including the thermal envelope of the processors, and any kind of adjusted tolerance between them. 

Given the processes we're talking about I assume that they are more efficient not less efficient than the old models. Therefore, I would assume that having a heatsink with larger fins but center material means increased airflow but less heat saturation and thermal load.

Again, that's a guess. But I think there was a fair amount of time between these two processors being put out.

Even today, it's super common that you secure parts for a single production run. After that production run, you can go back to your suppliers and try to get the same parts but likely a certain percentage of them will no longer be available or you'll have to go with a different supplier for a similar part. This is just how our world works because nearly everything is done in short-term batches with a lot of stuff not being continuously run off a production line for years and time.

A lot of times semiconductors will be around for many many years but a lot of things like passive components, heatsinks, standoffs, screws, and bolts, etc will be sourced every production run.

[johnnym]

I just want to identify the possible processors of an item I intend to purchase and the seller doesn't know and doesn't have a machine to test it. As you might know, I'm building OpenBSD/sgi on a dual R12000 @300 MHz Octane, for which I have no spare parts in regard to the PM. I am hence looking for possible spare parts for this Octane or extension parts to maybe outfit another Octane and share the build load where possible for example.

So back to the item, If it's based on R12000s I'm OK with it (because the PM then can be anything faster or equally fast to what I already have), if not I don't need it.

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UPDATE: Looks like I found the answer to my question, but only after making the post:

https://ordi-spare.com/en/spare-part-sgi...7-001.html shows a R10000 based dual module with cast aluminium heatsink. And https://wiki.preterhuman.net/SGI_Octane#CPU_Options confirms the part number. In addition it also lists a dual 270 MHz R12K PM, so my assumption above is not fully correct, even if the PMs with cast aluminium heatsinks were all R12K based.