Can these be used for crypto mining at any level of efficiency? I was able to mine GRLC back in the day on AWS spot instances at a VERY mild degree of profitability.
Doubtful, since these are just fully unlocked TU102 GPUs (same as the Titan RTX, 2080ti is the same TU102 GPU but partially locked at 4352 cores vs 4608 for the Quadro RTX 6000/8000 and Titan RTX). If you could be profitable with this at $1000/month then people would be flocking out to buy 2080tis for $1100 and getting 90-95% of the hashrate.
They wouldn't be available if they were profitable for that. Providers usually make you do extra verification to use these instances because people were at a time using them for that, not because it was profitable, but because they used stolen cloud accounts/cards.
not really, most cryptocurrency is at the stage where the only thing effective is a combination of custom ASICs and nearly free electricity. About twelve months ago I looked into mining ethereum with state of the art GPUs and it would not have had a reasonable ROI unless I was literally paying $0.00 per kWh. And that was before its value per coin dropped a lot.
When the value dropped, the network hashrate dropped and difficulty went down so things actually became profitable again.
The best time to mine is during the drops, not the highs, unless you follow buy high, sell low and don't believe the market will correct for the better again (which it has).
Of course, it depends on electricity prices, but it is profitable to mine ethereum, especially if you know how to tune the cards to maximize hash/consumption.
That said, mining is competitive and difficult and unless you are going to go really large, don't bother. If you are interested in learning about it, definitely experiment though don't expect to make a lot of money.