42 is the answer

[M344587487]

The question being how many GPUs would it take to knock VBCurtis off the top spot for first time LL testing. Such a farm would have these specs:

• 8 Titanium PSUs running at around the sweet spot
• 42 Radeon VII GPUs
• Cost ~£30k including taxes in the UK at current prices not considering a UPS
• Consume ~9.5kW not considering a UPS
• Knock out a PRP at the current wavefront every ~32 minutes
• Be a challenge to maintain and cool

That sounds great if power is cheap. A DIY solar farm sourced second hand for some thousands from a facility refreshing their renewables is probably advisable, with some wind to smooth out generation. And somewhere to put the ~70 solar panels, battery banks and gubbins it would take to provide most of the power. And a guy to install and maintain all of that unless you want your life to revolve around your prime farm, which funnily enough will probably literally be on a field as you're going the DIY route. Now we're on a field it makes the most sense to put the farm in a shipping container, another grand plus more to customise it to make it suitable to house a server. But now you have ~£40k of equipment £10k of which is sitting in plain view and easily nickable, better spend a couple of grand on security, a decent fence with barbed wire at least and a padlock or something. Now your quaint field looks like a drug lord's den and the black helicopter's are circling. The neighbour's stop talking to you and refer to you only as the number hermit. Paranoid and alone you shiver next to the warm glow of the container as you contemplate camo netting.

On second thought.

[axn]

Originally Posted by M344587487

The question being how many GPUs would it take to knock VBCurtis off the top spot for first time LL testing.

I think it is much easier to knock VBcurtis off the top spot. Now Curtis Cooper on the other hand ...

[M344587487]

Oops :P In that case it's near impossible to knock VBCurtis off as you'd somehow have to get him there first.

[kriesel]

Plan B: persuade 41 of your closest friends to install a Radeon VII and give you remote access.

[dcheuk]

According to Wikipedia

The supercomputer, OLCF-4 (or "Summit"), operated by DOE at Oak Ridge National Lab, has 27,648 Tesla V100 GPUs in there (13MW Power supply, probably more for AC cooling lol).

So, assuming your calculations holds and V100's performance is similarly to Radeon Vii (lol), it takes that lab 1.80 days to beat him.

As a side note, assuming each V100 graphics card cost the Department of Energy USD 10K per unit, that is USD 276,000,000 worth of graphics card in there.

[ATH]

I can see you are looking at the default top LL view:
https://www.mersenne.org/report_top_500_ll/

Which is the stats for the last 365 days
curtisc 15168 attempts : 365*24*60 minutes / 15168 ~ 34.7 minutes per LL test.

So with your setup with 1 LL every 32 minutes you would catch up on this yearly stat after ~ 337 days.

But if you then switch to the lifetime stats you will need a much bigger farm :) or it will take decades to catch up:

https://www.mersenne.org/report_top_...1-01&end_date=

[Uncwilly]

https://i.etsystatic.com/17914599/r/...81377_9mkj.jpg

[petrw1]

4.13 Million in the last 365 days is:

About 3 of my 2080Ti GPUs (Granted not LL GhzDays)
Or
About 115 of my 7820X CPUs

[VBCurtis]

Originally Posted by M344587487

Oops :P In that case it's near impossible to knock VBCurtis off as you'd somehow have to get him there first.

I retired from Mersenne searching in roughly 2004, when I discovered the LLR program and started testing k*2^n-1 forms. I don't think I have many credits from that Celeron-300 @ 504mhz, but I do still have the peltier cooler I used to get that overclock!