Talk:OpenPOWER

Magna systems' platforms

Penguin Computing made the Magna 1015, a Barreleye G1 system, but I can't figure out what platform the other Magna systems like the 2001, 2002, 2002S are.

• Magna 1015 datasheet
• Magna 2001 datasheet
• Magna 2002 datasheet
• Magna servers page - only showing Magna 2002S now

Torpcoms (talk) 01:30, 27 December 2017 (CST)

Monza vs LaGrange on AC922

I was under the impression that IBM used LaGrange for AC922 too. The pictures associated with the launch of AC922 (like this image) seems to indicate that they are using a module that's identical to what's been used for Zaius/Barreleye 2, seen on this page where they explicitly say they are using LaGrange (corroborated by lot of info on GitHub regarding Zaius). The modules in the IBM and Rackspace pictures have identical pinouts. Monza and LaGrange would probably not have identical arrangements of pins since the point of them are that they have different I/O. If I'm wrong, I'd be happy to read an explanation from someone who knows more. -- Henriok (talk) 17:13, 27 December 2017 (CST)

According to the XML files for Witherspoon the module is Monza: https://raw.githubusercontent.com/open-power/witherspoon-xml/master/witherspoon.xml . Any chance the AC922 is not based on Witherspoon? SiteAdmin (talk) 17:22, 27 December 2017 (CST)

Hmm.. that's a really good point. I'm more than willing to trust this source :) It's more plausible that IBM is not being correct in their promo pictures. "Just take any POWER9 module.. never mind the nitpickers on the Internet" :) Thanks! -- Henriok (talk) 06:20, 28 December 2017 (CST)

Since Monza and LaGrange have the same module size according to the IBM OpenPOWER portal, it seems possible they would share a pin arrangement, even if some of the pins are used differently.

I had asked about the difference between the different modules on Reddit's /r/OpenPOWER (talking with stwcx and talking with agangidi) and in addition to telling me about the same XML files for witherspoon as SiteAdmin mentioned, I was told that the Monza modules are meant for high performance analytics. The AC922 is marketed as for AI-powered analytics, so this looks to match up.

The main difference as I can tell between the LaGrange and Monza chips is the tradeoff of OpenCAPI lanes for XBus (used for SMP, communication between processors). Here's the table I made to visualise it:

POWER9 Nimbus Modules

	1 XBus	2 XBus
16 OpenCAPI lanes or less	Sforza (48 PCIe lanes)	LaGrange (42 PCIe lanes)
48 OpenCAPI lanes	Monza (34 PCIe lanes)

If the modules are different in IO only, wouldn't it be safe enough to share a physical socket? - Torpcoms (talk) 15:54, 28 December 2017 (CST)