Author Topic: Convert GPU PCI-E X16 to X8  (Read 1942 times)

tle

  • Full Member
  • ***
  • Posts: 232
  • Karma: +28/-0
    • View Profile
    • Ruby Journal
Convert GPU PCI-E X16 to X8
« on: April 20, 2020, 01:13:08 am »
My Radeon Vega 64 PCI-E 3.0 X16 card would not take advantage fully of the X16 PCI-E 4.0 X16 bandwidth. Plus the double slot design of this GPU would get in the way of the X8 slot of the Raptor Blackbird. So I bought the X16 to X8 adapter card on Aliexpress so I could install my GPU on the X8 slot. The hack works but I don’t really like it that much because the card profile would now be incompatible with closed PC based.

I wish that the future revision of Blackbird would swap position of X8 with X16 slot. Additionally the X8 slot should be open-ended so that X16 card could fit in perfectly without the needs of using adapter card.

UPDATE: I mod my X8 slot open ended https://youtu.be/93yEag-aryk
« Last Edit: May 17, 2020, 08:44:54 am by tle »
Faithful Linux enthusiast

FlyingBlackbird

  • Jr. Member
  • **
  • Posts: 95
  • Karma: +0/-0
    • View Profile
Re: Convert GPU PCI-E X16 to X8
« Reply #1 on: April 20, 2020, 06:17:45 am »
> I wish that the future revision of Blackbird would swap position of X8 with X16 slot.

Yes, this IMHO one of most urging limitations (only two PCIe slots and too narrow for x16 dual slot GPU cards if you want to use the x8 slot too).

My workaround would be (I still have no 2-slot GPU) an PCIe extension raiser adapter (50 EUR / 60 USD) which is eg. supported in my Fractal design define R6 case:

https://www.fractal-design.com/products/accessories/flex-vrc-25/black/

In the how-to video you can see how the GPU is mounted in another place (turned by 90 degrees).

This could also improve the cooling situation.

MPC7500

  • Sr. Member
  • ****
  • Posts: 346
  • Karma: +20/-1
    • View Profile
    • Twitter
Re: Convert GPU PCI-E X16 to X8
« Reply #2 on: April 20, 2020, 10:18:53 am »
I wish that the future revision of Blackbird would swap position of X8 with X16 slot. Additionally the X8 slot should be open-ended so that X16 card could fit in perfectly without the needs of using adapter card.

Second that and remove the f***ing USB port ...

MauryG5

  • Hero Member
  • *****
  • Posts: 542
  • Karma: +15/-1
    • View Profile
Re: Convert GPU PCI-E X16 to X8
« Reply #3 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...


tle

  • Full Member
  • ***
  • Posts: 232
  • Karma: +28/-0
    • View Profile
    • Ruby Journal
Re: Convert GPU PCI-E X16 to X8
« Reply #4 on: April 21, 2020, 04:00:56 am »
I wish that the future revision of Blackbird would swap position of X8 with X16 slot. Additionally the X8 slot should be open-ended so that X16 card could fit in perfectly without the needs of using adapter card.

Second that and remove the f***ing USB port ...

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.

Faithful Linux enthusiast

tle

  • Full Member
  • ***
  • Posts: 232
  • Karma: +28/-0
    • View Profile
    • Ruby Journal
Re: Convert GPU PCI-E X16 to X8
« Reply #5 on: April 21, 2020, 04:03:15 am »
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...

Most micro-ITX / mini-ITX motherboards on the market have PCI-E X16 next to the edge of the board.
« Last Edit: April 21, 2020, 07:59:46 pm by tle »
Faithful Linux enthusiast

MPC7500

  • Sr. Member
  • ****
  • Posts: 346
  • Karma: +20/-1
    • View Profile
    • Twitter
Re: Convert GPU PCI-E X16 to X8
« Reply #6 on: April 21, 2020, 09:37:04 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.

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

MauryG5

  • Hero Member
  • *****
  • Posts: 542
  • Karma: +15/-1
    • View Profile
Re: Convert GPU PCI-E X16 to X8
« Reply #7 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 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

  • Newbie
  • *
  • Posts: 14
  • Karma: +0/-0
    • View Profile
Re: Convert GPU PCI-E X16 to X8
« Reply #8 on: April 21, 2020, 05:19:32 pm »
Sforza's lanes are the highest so far in the 3 models. Sforza has 48 PCI-e lanes against 42 LaGrange …
Nimbus ModulePCIe 4OpenCAPI 3
Sforza48N/A
LaGrange4216
Monza3448
I 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.

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.
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.
« Last Edit: April 21, 2020, 05:22:10 pm by AbstractConcept »

MPC7500

  • Sr. Member
  • ****
  • Posts: 346
  • Karma: +20/-1
    • View Profile
    • Twitter
Re: Convert GPU PCI-E X16 to X8
« Reply #9 on: April 21, 2020, 05:45:33 pm »
Yeah, I got mixed up on that one. I thought LaGrange had the most PCIe lanes.

MauryG5

  • Hero Member
  • *****
  • Posts: 542
  • Karma: +15/-1
    • View Profile
Re: Convert GPU PCI-E X16 to X8
« Reply #10 on: April 22, 2020, 12:19:04 pm »
It is a good abstract concept, SATA ports cannot be eliminated, they are needed because they allow more people to use the peripherals at normal costs. Raptor made the Blackbird with the precise purpose of making a power system accessible to everyone and it did great. In the years to come, the choice will be wider and wider and there will also be a card with ATX form factor, which will be able to meet more requirements such as various equipment and who will want and can, will buy the one, which will have more RAM slots and more PCI-e slots available at a slightly higher cost. At the moment, for example, we are waiting to meet the Condor, which will be the first Power card with ATX shape and will mount Power 9 LaGrange.


tle

  • Full Member
  • ***
  • Posts: 232
  • Karma: +28/-0
    • View Profile
    • Ruby Journal
Re: Convert GPU PCI-E X16 to X8
« Reply #11 on: May 17, 2020, 08:44:19 am »
I finally decide to convert the X8 slot to open-ended.

Here is my YouTube https://youtu.be/93yEag-aryk
Faithful Linux enthusiast

q66

  • Guest
Re: Convert GPU PCI-E X16 to X8
« Reply #12 on: May 17, 2020, 01:04:06 pm »
you do realize that you will get the same bandwidth as PCIe 3.0 x8, right? You will not get the bandwidth of an x8 4.0, since per-lane you get the bandwidth of the negotiated PCIe version, times 8 lanes.

tle

  • Full Member
  • ***
  • Posts: 232
  • Karma: +28/-0
    • View Profile
    • Ruby Journal
Re: Convert GPU PCI-E X16 to X8
« Reply #13 on: May 17, 2020, 10:19:07 pm »
Yes I am fully aware. My GPU is last gen and could not take full bandwidth of PCI-E 3.0 X8
Faithful Linux enthusiast