Bought a used AMD VII, my first VII. It ran just fine in x16 slot (H110 btc motherboard).
Four WU at a time averaged 15 second per single work unit.
I put the VII, an S9100 and a pair of S9000 all on risers.
The VII slowed to 30 minutes per work unit. I assume this is AMD not letting me mine.
Anyway, it is back in the x16 slot and all boards are working fine. I have several more of those S9xxx boards to add to my H110 BTC. Eventually my "stats" will indicate I have 6 of those VII but there is actually only one.

Is there a VII firmware upgrade to allow running at full speed on an x1 slot?

Bought a used AMD VII, my first VII. It ran just fine in x16 slot (H110 btc motherboard).
Four WU at a time averaged 15 second per single work unit.
I put the VII, an S9100 and a pair of S9000 all on risers.
The VII slowed to 30 minutes per work unit. I assume this is AMD not letting me mine.
Anyway, it is back in the x16 slot and all boards are working fine. I have several more of those S9xxx boards to add to my H110 BTC. Eventually my "stats" will indicate I have 6 of those VII but there is actually only one.

Is there a VII firmware upgrade to allow running at full speed on an x1 slot?

I think it shows the slowness of the pci-e connection thru the riser as opposed to being plugged into the MB, what happens if you only run 1. 2 or 3 tasks at a time instead of the full 4 tasks on the riser?

The Amazon warehouse has more than a couple AMD VII's priced in the $350 to $400 range, all used.

I think it shows the slowness of the pci-e connection thru the riser as opposed to being plugged into the MB, what happens if you only run 1. 2 or 3 tasks at a time instead of the full 4 tasks on the riser?

The Amazon warehouse has more than a couple AMD VII's priced in the $350 to $400 range, all used.

The S9100 and the S9000 have no problems with the x1, all running 4 WU's concurrently.
There probably is a performance loss for projects that need more memory.
The PCIe generation is set to "Gen 1" for all slots else the VII would hog all the lanes and the other boards would not work at all.
My ViI was $300 + tax USD and I have a single used S9150 on order ($100). All use the same driver. Windows 10 thinks they are the "W" versions.

5			12/23/2022 3:41:33 AM	OpenCL: AMD/ATI GPU 0: AMD FirePro W8000 (driver version 3075.13, device version OpenCL 1.2 AMD-APP (3075.13), 6144MB, 6144MB available, 3226 GFLOPS peak)	
6			12/23/2022 3:41:33 AM	OpenCL: AMD/ATI GPU 1: AMD FirePro W8100 (driver version 3075.13, device version OpenCL 2.0 AMD-APP (3075.13), 12288MB, 12288MB available, 4219 GFLOPS peak)	
7			12/23/2022 3:41:33 AM	OpenCL: AMD/ATI GPU 2: AMD FirePro W8000 (driver version 3075.13, device version OpenCL 1.2 AMD-APP (3075.13), 6144MB, 6144MB available, 3226 GFLOPS peak)	
8			12/23/2022 3:41:33 AM	OpenCL: AMD/ATI GPU 3: AMD Radeon VII (driver version 3075.13 (PAL,HSAIL), device version OpenCL 2.0 AMD-APP (3075.13), 16368MB, 16368MB available, 13832 GFLOPS peak)	

Some double precision float performance from TechPowerUp for these AMD.
MilkyWay is the only project that uses GPU double precision FP extensively that I know of.
The S90x0 are the same form factor (heat sink usually fits) and use the same chip as the HD-7950

VII      3.360 TFLOPS
S9150    2.534 TFLOPS
S9100    2.109 TFLOPS
S90x0    0.804 TFLOPS

From my performance app
Time shown is for 4 concurrent so divide by 4 for each work unit.

There are 4 GPUs, units are minutes
Dev#   WU count  Avg and Std of avg
GPU0 WUs:327 -Stats- Avg:2.9(0.40)
GPU1 WUs:415 -Stats- Avg:2.3(0.31)
GPU2 WUs:329 -Stats- Avg:2.9(0.41)
GPU3 WUs:864 -Stats- Avg:0.8(0.10)

I am running 7.16.3 with my "fix" for the Milkyway timeout

Are you sure its just not a bad riser? They aren't very reliable. Milkyway doesn't really use much PCI-e lanes, but you will see improvements on fast cards running at least 8x anything less and it does hinder performance, but marginally.

Are you sure its just not a bad riser? They aren't very reliable. Milkyway doesn't really use much PCI-e lanes, but you will see improvements on fast cards running at least 8x anything less and it does hinder performance, but marginally.

I do not know what is happening. I read this article that indicates AMD is not trying to stop mining

Earlier today I remove the Vii from the X16 slot and put in in a new riser and new cable. I have a lot left over from when SETI went out of business.

I put the X1 connector into the X16 slot and the elapsed time went from just under a minute to 30 minutes. I actually did not let it run that long as it was obviously not working. I then move the X1 connector to an adjacent "black" slot that I knew was good was I had taken a riser out of it.

Same problem, same about 30 minutes to do a set of 4 work units.

All the other cards, S9150, S9100, S9000 all working fine 4 units each. All completing in 2-3 minutes except the VII

I checked GPUZ and system was running at same temperature and % load as when the work units took under 1 minute which seems totally wrong.
All slots on this H110 are set for Gen1. The mombo has 12 slots, 11 are X1. This system used to have about 9 NVidia boards of all type and ran SETI and Einstein.

I also checked the bios with GPUz and the Version & Date matches the bios in the techpowerup database of BIOS which indicates it is not a special "one-off" mining bios. If someone else is using risers with VII I would like to know the firmware version and how they did it.

I have no idea what is happening and have never seen a performance difference between X1 and X16 other than on the GPUGRID project. I looked through the credit performance leader and was unable to find any VII systems that had more than 2 VII.

I also noticed that my "mod" of boinc, 7.15.0, is used by the majority of credit leaders. I am working in a 7.21 version and am testing the windows version now.

For what it's worth, I tried one of those ribbon cable risers that have all the x1 wiring, not just the wiring in the USB3 type cable.
Same problem: VII slowed down terribly. It needs to be in an x16 slot yet crypto miners run the VII on USB3 risers so I am unsure what is happening.
The eBayer I bought the card from was a crypto miner and had no problem as all the cards were in x1 USB3 risers and suggested a bad risers but I tried several.

For what it's worth, I tried one of those ribbon cable risers that have all the x1 wiring, not just the wiring in the USB3 type cable.
Same problem: VII slowed down terribly. It needs to be in an x16 slot yet crypto miners run the VII on USB3 risers so I am unsure what is happening.
The eBayer I bought the card from was a crypto miner and had no problem as all the cards were in x1 USB3 risers and suggested a bad risers but I tried several.

A guy on Einstein was talking about using risers and said the key to the cabling is you need GOOD cabling not JUST cabling, he said just any cabling is flaky and will drop the signal all the time while the GOOD cabling will maintain the signal, I will try and ask him which is the GOOD stuff tonight and get back to you.