It should work out of the box. No bifurcation setting is needed. The 1st PCIE slot only gets 8 lines from 8700G.
1 Like
It’s important to use the correct nomenclature here to avoid misunderstandings:
-
Bifurcation is the term used when dividing PCIe Lanes routed to one physical PCIe slot, typically into 4 Lane “sets”. Example: A x16 PCIe slots gets 16 PCIe Lanes from the CPU, you want to use a passive bifurcation card for 4 NVMe M.2 SSDs so you choose to bifurcate this single PCIe slot into 4 “logical” PCIe slots with 4 Lanes each.
-
Muxing is the term used when the motherboard uses for example only 8 PCIe Lanes (Lanes 1,2,3,4,5,6,7,8) in the top CPU PCIe slot and the remaining 8 Lanes (Lanes 9,10,11,12,13,14,15,16) get routed to the second CPU PCIe Slot, both slots can then use up to 8 PCIe Lanes each.
-
The biggest Ryzen 8000G APUs only have Lanes 1-8, Lanes 9-16 do not exist (maybe used internally for the iGPU), this means with such an APU the second CPU PCIe Slot will always be dead.
-
But the first CPU PCIe Slot that gets Lanes 1-8 should be able to use PCIe Bifurcation to use two x4 devices in it (but hasn’t been confirmed by testing yet).
-
AM5 offers up to two additional motherboard M.2 slots with 4 CPU PCIe Lanes each, these are luckily still there with the 8700G. So in total you should be able to connect four x4 NVMe SSDs to CPU PCIe, two as a set in the bifurcated top CPU PCIe Slot and two individually in the regular M.2 slots.
-
Depending on the motherboard layout you might be able to add more M.2 SSDs that are connected via the chipset and not directly via CPU PCIe.
3 Likes
I got annoyed not getting answers to such banal Yes/No question so I took a chance and just ordered a 8700G with Kingston 32 GB DDR5-5600 ECC UDIMMs to test everything myself.
The test motherboard is going to be an ASUS ProArt X670E-CREATOR WIFI, ASUS’ memory support documentation looks promising, they also list the PRO 8700G but according to ASUS the regular 8700G is “validated” to do ECC, too.
Have about every possible product regarding PCIe Bifurcation, too so all questions can then be finally answered.
3 Likes
I am just saying. You don’t really need ECC. Problem solved.
Cancel your order if you want to save a few bucks. Here is what I ordered yesterday:
I have a 3090 in another rig and a dual10gig PCIEe v3 x4 card on the way, so I can test what happens when both are in.
I do not have a PCIE-NVME card of any kind, unfortunately.
As you can see, I also ordered the ECC memory
3 Likes
-
Don’t worry, I have general use for the parts - if the 8700G has functioning ECC. If not then it gets sent back within the return window and have to wait until I can get a PRO 8700G somewhere. I usually hate such behavior and never return stuff but I feel fine here since manufacturers don’t seem get their shit together regarding proper product documentation.
-
It’s also good to have multiple independent sources for claims, to not just have to trust one weirdo on a forum somewhere
-
My testing itch for January couldn’t be satisfied since Digi-Key shafted my Adaptec Tri-Mode HBA order (horrible customer service) so it’s nice to have a replacement with APU testing.
-
It’s also nice to be able to continue APU+ECC testing: Ryzen 5700X ECC reporting - #17 by aBav.Normie-Pleb
-
I can predict your future: Only the top CPU PCIe Slot will work on the ASUS ProArt B650-CREATOR (PCIe Lanes “1-8” can’t be routed to the second CPU PCIe slot) and of course the B650 Chipset PCIe slot.
- I disagree. One should not generalize specific requirements of other people.
6 Likes
Got everything except the DDR5 ECC UDIMMs, hope they’ll be here soon.
Edit:
Well, fuck:
But I’m still curious, maybe just like the numerous errors in AMD presentations and on websites this too is a false information and ECC actually works.
Also great that Tom’s Hardware credits Reddit as a source for this topic of contention and not this forum where it has been discussed for about a month.
3 Likes
Wow, it really sucks:
- Confirmed ECC is not working with the 8700G (menu option in the UEFI without function)
- NO PCIe Bifurcation Option for the 8 Lanes that get to the top CPU PCIe Slot (to be sure that there is no hidden “Auto” feature I installed a Delock 90091 with 2 x U.2 NVMe SSDs that is functioning fine on other (AM4) systems and only the first SSD is detected)
- IOMMU Option not present in the NBIO Options
(Tested on an ASUS ProArt X670E-CREATOR WIFI with latest BIOS 1904 (AGESA AM5 PI 1.1.0.2b), I have been using many AM4 ASUS motherboards so I generally know my way around their BIOSes)
Will make a feature comparison with a 7800X3D to add validity to my findings, this has been my very first AM5 system…
Will add photos later, have to take a hate nap now. Utterly disappointed.
If this is “as intended” the non-existent PCIe Bifurcation Feature would disqualify the 8000G APUs completely for me.
Would it help anyone if I recorded a BIOS Options walkthrough as a video?
@Wendell
Can you confirm the lack of any PCIe Bifurcation Options with Phoenix 1?
8 Likes
Yeah this us what inwas hinting at earlier. And why i didnt mention in review. I was 85% sure it wasnt going to be a thing
My experience has been bad with these fringe features on the apu. I was hoping updates would clean it up. I think theres juat 4 pcie timers in there which only lets you have 1x16 and 2 x4 or 2 x8 and 1x4 the rest being for periperhals and usb4.
I have legit udimm ecc but its not even silently correcting the errors ive induced it seems.
4 Likes
- And AM5 Zen 5 CPUs are said to have the same IO Die as Zen 4 Ryzen 7000 CPUs meaning seemingly no hope there to get fully-featured 48 Gbit HDMI 2.1 with AV1 Decode and Encode until at least Zen 6 if you want ECC + PCIe flexibility
Zen 2 4000G and Zen 3 5000G APUs could do PCIe Bifurcation, you could do:
- x4 (to the chipset)
- x4 dedicated M.2 NVMe slot
- x4_x4 in one CPU PCIe slot
- x8 in the other CPU PCIe slot
The 8000G APUs actually are a significant downgrade regarding PCIe flexibility
5 Likes
At least now we know. Thank you so much for confirming and let’s hope some future upgrades to BIOS make a few changes, although I think Wendell is correct unfortunately that Bifurb will be limited
Some additional behavioral information regarding memory, maybe it helps someone:
-
Have been testing the 8700G with an ASUS ProArt X670E-CREATOR WIFI and 4 x 32 GB DDR5-5600 ECC UDIMM Kingston KSM56E46BD8KM-32HA memory with SK Hynix A-Die.
-
This memory doesn’t have any XMP or EXPO stuff, it’s just standard JEDEC with DDR5-5600 at 1.1 V.
-
With 2 modules (64 GB in total) the frequency defaults to DDR5-5200
-
With 2 modules just choosing DDR5-5600 works fine
-
With 4 modules (128 GB in total) the frequency defaults to DDR5-3600
-
With 4 modules you can just set it to DDR5-4400 and it still works
-
Anything above DDR5-4400 with 4 modules needs manual work (unfortunately have 0 experience with DDR5 yet)
1 Like
As this doesn’t support ECC, I’ll be waiting for a potential 8750G (or better even 8750GE). My main purpose is to use it in a server and use the iGPU for (Plex) HW transcoding. These above mentioned downside don’t really affect my use case, I assume.
Can you tell me something about HW transcodeing performance with Plex? Eg. How many simultanous streams for 1080p, 4K HDR/DV and if somehow possible AV1?
Hi and welcome to the forum!
I have never used Plex before, I’ll try to get to it before I get rid of the 8700G, a single month of that subscription to be able to use the Media Server + Hardware Transcoding features won’t kill me and maybe I can earn some Karma points for life in general.
The 8700G is the only hardware with AV1 Encoding I currently have, all other parts only do AV1 decoding (NVIDIA 30 series dGPUs, Ryzen 7800X3D).
Can you give me a detailed list of all tests that would interest you?
PS: I wouldn’t get a “GE” variant, these are just lower binned trash dies compared to the regular versions that can’t do higher frequencies without higher voltages, if you want to limit its power draw, just select a lower TDP mode in the UEFI of your motherboard.
Reducing PPT etc. works fine with AMD PRO APUs, only increasing the various limits is unfortunately blocked by AMD making overclocking essentially meaningless with PRO APUs
(As soon as an actual load hits the PRO APU its “unlocked” frequency drops down since it’s restrained by the socket power PPT and EDC current limits)
Thanks a lot for the offer. Unfortunately, it seems like Plex doesn’t offer to transcode to AV1, currently. Only AVC/h264 at 20 MBit/s max.
But at least it would be intersting to see a high bitrate AV1 4K HDR/DV test file being transcoded to AVC SDR 1080p@20Mbit/s. How many simultanous streams before buffering starts. This way HW decoding of AV1 while encoding to AVC can be tested. Maybe, outside of Plex, there’s a way to even test AV1 to AV1 transcoding - having a high bitrate AV1 source file and transcoding it to AV1 of lower bitrate or resolution. That might be a thing of the future of Plex.
Don’t know how to go on with testing, on my system the AMD GPU drivers constantly crash, you can provoke it by just going through the driver control menus. Without “intensive GPU load” for example using the 2D Windows desktop and browsing it happens less often but still regularly.
- Win 11 23H2 installed on a secure-erased SATA SSD
- Setup USB thumb drive created freshly with Microsoft’s Media Creation Tool
- Tried to reinstall drivers (24.1.1) after deinstalling them with DDU
- Tried the motherboard HDMI and USB-C/Thunderbolt 4 display output ports
- Tried using HDMI as well as DisplayPort as a connection for the display, no change
- Tried reinstalling Windows, no change
- Tried only 2 instead of 4 memory modules
- Tried reseating the APU
Pretty much a shit show
1 Like
- By contrast the 7800X3D’s iGPU works completely fine with the exact same parts and drivers.
1 Like
Does 7800X3D work with ECC?
After some research it seems AMD has still some issues with encode quality, idle power consumption and possibly drivers and support in Unraid, with the stock kernel.
Thinking about going with a combination of Intel Xeon E-2468 and Intel Arc A380 instead.
1 Like
Encode performance has been a mixed bag on AMD, you need to crank up the bit rate to get on par vs QuickSync esp for a TV DVR box as sports ball leads to heavy motion blur.
1 Like