GPU hangs up at Win 11 Loading Circle.

[sacentre]

My Gigabyte GTX 1660 Mini Ti GPU has started to hanging up my system during the Win 11 loading circle. This happens immediately after the POST Bleep.  If I power down (long press on power button) and reboot, the same thing happens. If I press reset, I get 5 long bleeps.

Very rarely, the boot will complete and once booted the GPU and PC work perfectly normally then the issue re-appears on the next boot.

There are many reports of similar behavior on the net and I've spent hours trawling through them but so far, I've not found any information that seems to apply to my case.  Mostly, the suggestions appear to be related to software and driver issues but I am tempted to think this is a hardware problem. If I remove the GPU, and use the on-board DP or HDMI port, my system behaves normally. If I re-install it, the issue re-appears.

The GPU is quite old so it's quite possible there's some component failure. I am prepared to replace it but am hoping there might be some fix I'm unaware of. I can't think of anything that would make the GPU do this on 3 different PCs so it's possible I've already answered my own question.

What I've tried.
 
1. Re-installed a fresh copy of Windows 11 including the most recent driver for this GPU from the Gigabyte web site. 
2. Replaced the SSD and installed a fresh copy of Windows. Same result.
3. Installed the GPU in another PC running Windows 11 and then a third with no hard disk so there were no drivers or software present. Same result.

This is a long shot, I realise but if anyone can suggest a fix short of binning the GPU, I'd be very grateful.

Probably not relevant but my system specs are:
Gigabyte Z790 Aorus Elite AX ICE rev 1.0 16GB DDR5 RAM
Windows 11 24H2 (Build 26100.3915)
Gigabyte GTX1660 Mini Ti 6GB (driver 32.0.15.7246)

Thanks for reading.

[dmdilks]

By any chance have you try the card in the 3.0 slot at the bottom? One other thing you could try is boot legacy vs UEFi. I try to look at the book but it doesn't. I think if you change CSM too it might help.

[sacentre]

By any chance have you try the card in the 3.0 slot at the bottom? One other thing you could try is boot legacy vs UEFi. I try to look at the book but it doesn't. I think if you change CSM too it might help.

Thanks for the input. I was desperately hoping that this issue might turn out to be some setting like that which I'd overlooked (a frequent occurrence with me) so I tried

CSM                       Enable/Disable 
Internal Graphics     Enable/Disable
Other PCIe Devices  UEFI/Legacy

Strangely, it booted correctly once after changing the CSM setting. Thereafter, it was back to the same behavior and other than a few BSODs and 5-bleep sequences nothing changed.  I simply couldn't get it to boot a second time. Weird.

I'm reluctant to replace the card as yet, since firstly, I haven't established for sure that it's faulty and secondly, the recent obscene increases in price of similar cards.

Thanks again.