PC Graphics

[Skuldwyrm]

I can't find info, or tests about the ned 9070 and 9070XT cards and what they support.
Per wikipedia UHBR20 is available from Displayport 2.1 onwards.

The 7900 XTX had UHB13.5 (54Gbps).
Sadly it can't deliver uncompressed 4K 240Hz 10bit to my OLED (which has Displayport 2.1 UHBR20).

9070 XT seems like a good buy on it's own, but if AMD still only has UHB13.5, the new card would be a downgrade in memory (from 24GB to 16GB) and a slight downgrade in raster performance.
The improved Raytracing and AI stuff is nice, but not enough to replace my 7900 XTX.

But... if the 9070XT has UHBR20 then I might be tempted to get it (and put the 7090 XTX into a older box for AI/LLM/rending/etc. stuff).

There is one website and one video that list UHBR13.5 but I have no clue where they got their info, I doubt they actually tested it with a UHBR20 display.

And there is no info on AMD's pages, nor on card manufacturer pages.

[fsadough]

UHBR20 is tied to DP 2.1 specification and not to the GPU. Radeon RX 9070 supports DisplayPort 2.1

[Skuldwyrm]

So you are saying the 9070 and the 9070 XTX can do UHBR20 / 80Gbps ?

I don't think you understood my question.

Because I do not want to buy the new card, boot up and in the AMD driver software see it say "Current Link Settings 13.5 Gbps x 4" (which is UHBR13.5 / 54Gbps)

when it's supposed to say "Current Link Settings  20 Gbps x 4" (which is UHBR20 / 80Gbps)
And then have to return my card, and drum my fingers and wait for the major competing brand to be available, because they are actually listed with specs saying they support UHBR20.

Currently with the 7900 XTX i have to use CRU to tweak the EDID timings for 240Hz 4K at 8bit, which makes the card happy and allow UHBR13.5.
Without tweaking with CRU the card drops to UHBR10 with DSC (Display Stream Compression) enabled.
This is due to the bandwidth limit of the Pixel Clock on the card (which drives the Displayport output).

If the 9070 XTX truly can do UHBR20, then I would be able to do 240Hz 4K at 8bit or even 10bit without having to mess with CRU, and without DSC enabled.

I do a lot of productivity stuff so Id'a rather not have DSC active, also if gaming, and taking advantage of of the new RDNA upscaling and framegen there is enough "noise/artifacts" that I don't want to layer DSC on top of that.
  

[fsadough]

Your concern is kinda related to the marketing strategy between AMD and competitor. I explained to you in my previous comment that UHBR is a DisplayPort spec by VESA standards and not GPU/ASIC related. When we specify that Radeon RX 9070 supports DP 2.1 then it means we follow the specs of VESA.

If AMD driver software says "Current Link Settings 13.5 Gbps x 4" (which is UHBR13.5 / 54Gbps), this could have other root causes, like a bad cable/adapter (DP80 Cable required for UHBR20) or corrupt EDID by the monitor.

All Radeon RX 9070 series are made by AIB partners like ASUS, Gigabyte, MSI and so on and we have no influence on how they market the product.

1. DP 2.x supports DSC & UHBR20
2. 4K@240Hz 10bpc requires 68.56 Gbits/s and hence supported by UHBR20=77.37 Gbits/s
3. UHBR20 is supported by DP 2.1 as per VESA standards

Please contact the AIB partner of your choice if you specifically need their confirmation on UHBR20 support by Radeon RX 9070 series 

[Skuldwyrm]

I still can't see how this is possible.

The RX 7900 XTX can only do UHBR13.5, despite following Displayport 2.1 spec.
Ad it's not a bad cable as I have both manufactuer 80Gbps (DP80) cable from the display manufaturer, as well as one of the new VESA certified 80GBps (DP80) cables.

You are saying the RX 9070 XT can do UHBR20, and if it can't then it's either a bad cable or the AIB that has decided to limit the AMD RDNA4 chip to only support UHBR13.5 and not UHBR20 ?

You are correct about marketing strategy, as in the use of Displayport 2.1a and Displayport 2.1b, these are both Displayport 2.1, but the difference her is that there are confirmation that the competitor can do UHBR20, but none for AMD.

This AMD slide show that the AMD Radiance Display Engine supports DP2.1a and DP2.1b.
As far as I can tell difference between 2.1b and 2.1a is in the cable spec (to allow a powered cable for longer cable lengths than a meter). DisplayPort 2.1 / 2.1a / 2.1b all support UHBR20, as you say it's part of the spec.

What I am saying is that the AMD RDE does not have a bandwidth specified either by AMD or AIBs, UHBR20 support is not a requirement for DisplayPort 2.x, it is optional.
As you said UHBR20=77.37 Gbits/s and 4K@240Hz 10bpc requires 68.56 Gbits/s falls within that.

But the only known AMD card (GPU) so far that actually can do UHBR20 is the AMD W7900 Pro card, ironically you have  Radeon PRO logo as your avatar.

People where expecting the new RDNA series to fully support 4 lanes of UHBR20 (which equals 80Gbps bandwidth maximum). So far only one website (Techpowerup) and one youtuber (Linus Tech tips) has mentioned the RX 9070 XT's UHBR speed as UHBR13.5 (54Gbps).

But as I said in my initial post, I do not trust single sources, and when this info was lacking from all AMD marketing material, from AIB specs sheets for the cards, and even from AMD's own web pages about the new 9000 series cards, I have to ask.

I asked one of the largest suppliers of AMD cards in Norway, and they just liked to the Linus Tech Tips video.
While one of the second largest suppliers said that this was not info they could get but I had to contact the board manufacturer.
Do you know how hard it is to get in contact with the board manufacturers, "just like that" ?

Are there actual reasons why this generation the information is "unavailable" ? That maybe some of the new GPUs have defects so that they can't do UHBR20 ?

Because otherwise saying that the new card supports DisplayPort 2.1 therefore UHBR20 is supported, but the GPU/card do not have enough bandwidth in the Pixel Clock to actually be able to do UHBR20, would per Norwegian marketing laws be considered "false marketing".
So in that case, not listing UHB20 when not all of the 9070 XT cards can do it is a sneaky way as it's not marketed with that spec info.

This year in frustrating for those who wish to buy GPUs. the AMD competitor has a "missing ROP" scandal going, and now it seems there is a "AMD can't do UHB20" situation brewing? (because the AMD competitor seems to be able to do this with their new series)

I assume you have somebody's ear on the technical side of AMDs staff that you could reach.

I'm begging you to please ask a engineer or tech rep at AMD for me, since they most likely have several of the various AIB cards available for testing, and ask them "Can any of the current cards actually do UHBR20, can the RDNA GPU do it? Or is there a defect or bandwidth limitation in all RDNA GPU chips?"

Because there is no way I'm going to spend several thousands of my native currency to buy one of the new card, test it, find that it can't do UHBR20, return or RMA it (defect card), ten buy a different brand, test, and return or RMA that one. It's difficult enough to get just any 9070 XT card, there is no way I can get and test each brand, it would take months and waste everyones time.


I've tried to explain this as best as I can, if you can still not understand me, then I don't know how to explain it, your technical knowledge should in theory be better than mine, but currently it seems not to be so?

I will try to send emails to all AIBs but I doubt they'll answer, especially if this is a limitation of the new chip (just like with RDNA3) that the AIB has no control over.

[fsadough]

I have to make corrections to my statement before. DP 2.1 is a superset spec that includes UHBR10/13.5/20 modes. We can claim DP 2.1 with any one of those levels.

We do not manufacture the consumer RDNA4 cards, so the accurate info will come from the AIBs. However my contact claims that the RDNA4 consumer cards should be supporting UHBR13.5 ONLY. I will contact Gigabyte through my channels and see what they say. Sorry about the confusion.