Raptor Computing Systems Hardware > Mod Zone

Convert GPU PCI-E X16 to X8

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tle:

--- Quote from: MauryG5 on April 20, 2020, 01:33:09 pm ---Guys, I don't think it's as simple as you might think this slot 8 above and 16 below. The Blackbird is a micro ATX card which means that it has to be compact and give you the possibility to install a 16 connector card and an 8/4/1 connector card. If they inverted the slot position, considering that the 16 slot is used for almost all people, for the graphics card, putting it underneath, there would no longer be the space required to install the cards that mainly need that slot. Moreover, you have to consider that today most graphics cards use such a shape that the upper slot 16 is precise and also the other motherboards of other computers are designed in the same way, the thing is universal for everyone for obvious reasons of optimized space. Raptor has to think about most of the options that are used today and in percentage, the cards on the market today are used with that configuration. What I think, we need to complete the range of motherboards dedicated to Power, is a card with ATX form factor, like the Condor or similar, in this way we will have more possibilities to install the various add-on cards...

--- End quote ---

Most micro-ITX / mini-ITX motherboards on the market have PCI-E X16 next to the edge of the board.

MPC7500:

--- Quote from: tle on April 21, 2020, 04:00:56 am ---[I second that. Please also get rid of all SATA ports. SATA is now a thing of the past or replace SATA with SAS (but I do not think it would be a good idea because of cost factor).

I also think the board should come with at least two M2 port. One is for NVMe SSD and the other for Wifi.

--- End quote ---

Yes, but the problem is the limited PCIe lanes of the Sforza CPU. LaGrange has more, but is also more expensive for sure.

MauryG5:
Sforza's lanes are the highest so far in the 3 models. Sforza has 48 PCI-e lanes against 42 LAGrange and 16 OpenCapi 2.0 lanes, Monza has 34 PCI-e lanes, 48 and OpenCapi 2.0 lanes. The problem is not in the lanes so, only in the construction of the card and the spaces to use.

AbstractConcept:

--- Quote from: MauryG5 on April 21, 2020, 01:39:06 pm ---Sforza's lanes are the highest so far in the 3 models. Sforza has 48 PCI-e lanes against 42 LaGrange …

--- End quote ---
Nimbus ModulePCIe 4OpenCAPI 3Sforza48N/ALaGrange4216Monza3448I put that into a bbcode table for easier reading, though a more detailed version exists on the POWER9 RCS Wiki page. I would also note that OpenCAPI starts with version 3, as it continues the CAPI numbering. The Sforza modules, and therefore Talos II & Blackbird actually have CAPI 2 support, as it runs on top of PCIe 4 physical interface.


--- Quote from: tle on April 21, 2020, 04:00:56 am ---Please also get rid of all SATA ports. SATA is now a thing of the past or replace SATA with SAS (but I do not think it would be a good idea because of cost factor).

I also think the board should come with at least two M2 port. One is for NVMe SSD and the other for Wifi.

--- End quote ---
Maybe not in future boards, but I am definitely happy to see SATA support on Blackbird. For those of us with limited resources, being able to use cheaper SATA SSDs or even HDDs makes getting into OpenPOWER that much easier; especially when already dealing with the hard requirements of:
• non-commodity mainboard
• non-commodity CPU
• non-commodity heatsink
• more expensive ECC RAM
Having cost savings possible somewhere, such as in storage, is a godsend.

I should note, the reason for SATA rather than SAS is partly due to the SATA controller having open source firmware actually I think it has no firmware at all. I remember reading somewhere that there is little to no hope of the any SAS controller being clean-room reimplemented in open source code, unlike the NIC.

MPC7500:
Yeah, I got mixed up on that one. I thought LaGrange had the most PCIe lanes.

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