Author Topic: Imprecise EATX terminology considered harmful - SSI-EEB  (Read 293 times)

AbstractConcept

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Imprecise EATX terminology considered harmful - SSI-EEB
« on: March 31, 2020, 04:53:13 pm »
I was initially quite confused at the number of standoff and case size issues I have heard regarding the Talos II mainboard. For examples, see the RCS Wiki’s Hardware Compatibility List for Talos II, which has an entire section for problematic cases:
https://wiki.raptorcs.com/wiki/Talos_II/Hardware_Compatibility_List#Problematic_Cases

However, Gamers Nexus recently published a lengthy article & video about the ambiguity inherent in the “EATX” marketing, which seems to be the explanation I was looking for:
https://www.gamersnexus.net/guides/3566-e-atx-is-a-lie-vs-xl-atx-eeb-ceb
https://youtube.com/watch?v=54VJwwLRJBk
Apparently, the real underlying specification for elongated ATX boards with dimensions of 305 mm × 330 mm (12” × 13”) mainboards is SSI-EEB, whereas EATX is a marketing term that encompasses a wide variety of board sizes whose front-to-back measurement is greater than 244 mm (9.6”) but less than or equal to 330 mm (13”).

I think it would be extremely helpful to customers to make it clear that Talos II is an SSI-EEB mainboard, with a footnote warning that while some case manufacturers may market EEB cases as EATX or E-ATX, cases incompatible with EEB may also be marketed as EATX/E-ATX.

For the curious, SSI documents appear to have been moved to the SNIA’s website:
https://www.snia.org/standards/industry-reference

q66

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #1 on: April 03, 2020, 08:48:45 am »
talos 2 is neither EATX nor SSI-EEB, it's a supermicro-compatible format with the physical dimensions of SSI-EEB but incorrect hole positions, in a way saying SSI-EEB would be less accurate than saying EATX

MPC7500

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #2 on: April 03, 2020, 05:16:12 pm »
Tl;dr: E-ATX is a shithole. If I wasn't sure about the space in the chassis, I'd choose SSI-EEB.

This would also mean that any E-ATX chassis would be compatible with the TalosII. But this is not the case.
When you ask manufacturers (regarding E-ATX) if the case is 12" x 13" compatible, some say no. For example PHANTEKS Eclipse P300.
And as far as I know Supermicro's form factor for server boards is EE-ATX, which TalosII is also not.

AbstractConcept

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #3 on: April 03, 2020, 10:44:09 pm »
Looking at the board images on the wiki, it looks like the Talos II mainboard uses the SSI EEB alternate F′ and J′ mounting locations from SSI EEB 2011 v1.0.1, but the C mounting location is missing. Instead we have a location between A and C. Old versions of SSI EEB seem have this location as it seems to date back to the original AT specification; it is labelled “G” in version 1.0, and unlabelled in version 3.0, before being completely removed in version 3.5. This was before SSI relabelled their mounting locations to match ATX; were they to add it back now, as an alternate to location C, it would probably be labelled C′.

The ATX specification does have this missing mounting location, but calls it B, and only uses it for microATX and in earlier versions miniATX. To quote the ATX v2.2 specification, “The hole at B in Figure 2 was previously required along the rear edge of the board. This location is not required for ATX designs.” Older versions of ATX also mention the F′ mounting location, calling it E instead.

Sounds like to be certain it will fit the Talos II board, one should look for an SSI EEB chassis (for mounting locations F′/E and J′) with microATX support (for mounting location B). As Gamers Nexus points out, chassis with “EATX” marketing might not support the alternate mounting locations, of which Talos II needs F′ and J′. The only issue with a properly complaint SSI EEB chassis would therefore be the potential absence of the microATX mounting location B.

There does appear to be an absence of components where the C mounting location would be. I am quite curious if someone from Raptor could answer, why was this non-EEB B/C′ location chosen? Are there trace routing issues that I cannot see preventing the use of location C?



Sources for specifications:
SSI-EEB 2011 v1.01 - most recent EEB spec, I think
SSI-EEB 2008 v1.01 - contains revision history, unlike 2011 v1.01
SSI EEB v3.51 (from the Internet Archive)
SSI EEB v3.0 (from the Internet Archive)
SSI EEB v1.0 (from the Internet Archive)
ATX v2.2 (from the Internet Archive)
ATX v2.1 (from the Internet Archive)
ATX v2.03 (from the Internet Archive)
« Last Edit: April 03, 2020, 11:14:24 pm by AbstractConcept »

MPC7500

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #4 on: April 04, 2020, 06:17:53 pm »
For E-ATX mainboards I would definitely go for a Dune Pro.

ClassicHasClass

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #5 on: April 05, 2020, 11:52:57 am »
Is that an April Fools joke? It looks like a Mac Pro ripoff.

AbstractConcept

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Re: Imprecise EATX terminology considered harmful - SSI-EEB
« Reply #6 on: April 19, 2020, 11:18:56 pm »
Is that an April Fools joke? It looks like a Mac Pro ripoff.
It appears to be a real product, and it is also definitely a Mac Pro rip-off. Linus Tech Tips made a video with a prototype a while ago, but I have not heard anything recently about it.



Returning to the actual topic, Talos II board size and mounting/standoff locations, it would be helpful to hear something official from Raptor Engineering/Computing before I start making corrections to the wiki.

I am also purely curious about…
There does appear to be an absence of components where the C mounting location would be. I am quite curious if someone from Raptor could answer, why was this non-EEB B/C′ location chosen? Are there trace routing issues that I cannot see preventing the use of location C?