Re: Old NVIDIA card, new FreeBSD = failure?

From: Stefan Esser <se_at_freebsd.org>
Date: Sun, 27 Jun 2021 13:45:29 UTC
Am 27.06.21 um 13:55 schrieb Robert Huff:
> 
> Greg:
> 
>>   >	b) I have a very limited budget, and would ideally like to be
>>   >		able to use this on older systems - say ones with a PCIe 2.0
>>   >		expansion slot.
>>   
>>   No conflict here: PCI Express generations are all backward and
>>   forward compatible. You can run the newest gen4 cards in gen2
>>   slots just fine (obviously at gen2 bandwidth).
> 
> 	As Johnny Carson used to say: "I did not know that."  
> 	<inhales; exhales>
> 	So now I'm back to the question: what is the earliest GCN version
> actively supported by amdgpu and drm(-kmod/-current-kmod)?  More
> correctly: where is this documented?  I can look it up myself.

Hi Robert,

I've got a passively cooled R7 250E (Cap Verde Pro) with 2 GB video RAM
(probably identical to the GDDR5 version of the Radeon HD 7750).

All technical details can be found in Wikipedia:

	https://en.wikipedia.org/wiki/Radeon_HD_7000_series
	https://en.wikipedia.org/wiki/Radeon_Rx_200_series

It is a GCN 1st gen. card and supported by the xf86-video-amdgpu driver
and the DRM kmods and libva drivers.

I would not get a lower end card, they are neither cheaper nor more power
efficient (idle power of 10 W, 50 W max., allowing for a very silent fan
or even passive cooling in a case with forced airflow).

The HD 7790 is already GCN 2nd gen., but probably harder to get, and at
$70 about twice as expensive as a HD 7750 on eBay. All R5 240 and higher
cards should work as well (R5 220/230/235 are Terascale cards).

The only drawback compared to a modern card is raw performance (but the
7750 is already faster than today's typical on-chip VGAs) and lack of
HW decoding of modern video codecs like VP9.

Regards, STefan