Info PrimeGrid Challenges 2025

[Skillz]

It seems that running the tasks 2 threads is the best PPD wise. Out of two CPUs tested the 2 threaded tasks had the highest PPD with 4 threaded tasks on its heels. This was done on physical cores, no SMT or HT.

 

[Markfw]

GPUs for me are set at unlimited, unlimited. A mix of 4070 and 3070. One at a time.
I have 5950x and 9950x cpus and will run 4 tasks, 4 threads. No SMT and pin them to cores.
This is how I ran it in February's challenge at the end in hopes of finding a prime.

So running CPUs is not a waste of power compared to GPUs ?

 

[Icecold]

A 4090 can do roughly twice the number of GFN 18 tasks per day as a 7950x(while using at least double the power). A 4090 does less than double the tasks per day as a 9950x. Any AVX-512 capable CPU should either be more efficient than a GPU or at least be pretty competitive from a power efficiency perspective at GFN 18.

 

[Markfw]

A 4090 can do roughly twice the number of GFN 18 tasks per day as a 7950x(while using at least double the power). A 4090 does less than double the tasks per day as a 9950x. Any AVX-512 capable CPU should either be more efficient than a GPU or at least be pretty competitive from a power efficiency perspective at GFN 18.

So, a 9954 Zen 4 64 core. How would you configure that ?

 

[Icecold]

So, a 9954 Zen 4 64 core. How would you configure that ?

I would do 2 threads per task, with either SMT off in the bios or BOINC set to use 50% of CPU's, and pinned to physical cores with Lasso or a Linux script if it's Linux. I tested that on my dual 9534 and it was the most optimal so it should translate to your Genoa 64 core machines as well. With that configuration a single 9534 would do roughly the output of 1.5 4090's on GFN-18, my dual 9534 should do roughly the equivalent of 3 4090's on GFN 18. Your 9554's should do even better than a 9534 presumably.

 

[Markfw]

I would do 2 threads per task, with either SMT off in the bios or BOINC set to use 50% of CPU's, and pinned to physical cores with Lasso or a Linux script if it's Linux. I tested that on my dual 9534 and it was the most optimal so it should translate to your Genoa 64 core machines as well. With that configuration a single 9534 would do roughly the output of 1.5 4090's on GFN-18, my dual 9534 should do roughly the equivalent of 3 4090's on GFN 18. Your 9554's should do even better than a 9534 presumably.

Thanks ! Maybe I will turn a few on for this !

Edit: My Turin should also be a contest, with the avx-512 capability of the 9950x.

 

[Icecold]

Thanks ! Maybe I will turn a few on for this !

Edit: My Turin should also be a contest, with the avx-512 capability of the 9950x.

Yeah the Turin and Genoas should do really well at it and be really power efficient as well. Your 9950x's will also. And 7950x's also to a somewhat lesser extent. I'm not sure how much hardware you plan on running in the challenge, but if it were me I would probably prioritize running your Genoas, Turin and 9950x's before any video cards as long as you plan on using task pinning or lasso. Running on video cards is nice because you don't have to worry about task pinning or lasso though.

 

[Markfw]

Yeah the Turin and Genoas should do really well at it and be really power efficient as well. Your 9950x's will also. And 7950x's also to a somewhat lesser extent. I'm not sure how much hardware you plan on running in the challenge, but if it were me I would probably prioritize running your Genoas, Turin and 9950x's before any video cards as long as you plan on using task pinning or lasso. Running on video cards is nice because you don't have to worry about task pinning or lasso though.

2 x 32 with lasso for the 9554's and the Turin, and the 9950x will be 2 x 8 with lasso, and the 7950x's will do WCG and Rosetta. Of course the 4080's and 4090s will do PG.

At least that's the plan.

 

[Markfw]

OK, a little over 28 hours to go on this one. You guys ready ?

 

[Skillz]

I will most likely get there on time and late at the same time. Probably going to have to do a rolling start since I'll be on the road 2 or 3 hours before into a 4 and a half hour trip.

 

[Markfw]

A little over 3 hours t go. Mine are all powered up. Waiting for config, then I will be ready !

 

[Markfw]

9 minutes to go. In preparation of the heat, (its already 61f outside and hotter the upcoming week) I have every window and door open. The AC is set for 86, as thats as hot as I can stand it, but I fully expect it to come on. 9 minutes to go, and F@H has to get shut off.

 

[Markfw]

OK, I need some help. I can't get it to use GPU and CPU. The config is set to it in PG and the cpu number is 95% as always, but it won't use CPU on anything that has a GPU.

and as an aside, no PG stats update ???? 22 minutes later.

 

[mmonnin03]

I always split my CPU and GPU work between separate BOINC instances. The client is dumb

 

[Icecold]

OK, I need some help. I can't get it to use GPU and CPU. The config is set to it in PG and the cpu number is 95% as always, but it won't use CPU on anything that has a GPU.

and as an aside, no PG stats update ???? 22 minutes later.

Are those machines set to the default venue? (home, school, work, pluto, etc.) It's set to run GFN 18 on both CPU and GPU in the Primegrid website preferences? Do you have 'Max # of simultaneous PrimeGrid tasks' set on the Primegrid website? That should be unlimited. I'm running CPU and GPU work units in the same client without any issues.

These stats update every 15 minutes or so - https://www.primegrid.com/challenge/2025_2/top_teams.html and https://www.primegrid.com/challenge/2025_2/top_users.html

 

[Markfw]

Are those machines set to the default venue? (home, school, work, pluto, etc.) It's set to run GFN 18 on both CPU and GPU in the Primegrid website preferences? Do you have 'Max # of simultaneous PrimeGrid tasks' set on the Primegrid website? That should be unlimited. I'm running CPU and GPU work units in the same client without any issues.

These stats update every 15 minutes or so - https://www.primegrid.com/challenge/2025_2/top_teams.html and https://www.primegrid.com/challenge/2025_2/top_users.html

Stats, same problem as last time. I have to kill the stats URL and redo with the new challenge. Stupid me.

As to the venue, I have 5 variants, as I have 5 combos. cpu+GPU in 3 flavors, CPU only in 2 flavors. Whats odd, is the only one forking the way its supposed to, is the 9950x. I have others of the same flavor, and updated in boinctasks to be sure, but the others won't do both. And yes, the BOINC cpu% is 100%, but 95% of the CPUs. works fine in F@H.

 

[Icecold]

Stats, same problem as last time. I have to kill the stats URL and redo with the new challenge. Stupid me.

As to the venue, I have 5 variants, as I have 5 combos. cpu+GPU in 3 flavors, CPU only in 2 flavors. Whats odd, is the only one forking the way its supposed to, is the 9950x. I have others of the same flavor, and updated in boinctasks to be sure, but the others won't do both. And yes, the BOINC cpu% is 100%, but 95% of the CPUs. works fine in F@H.

If you could post some screenshots from the Primegrid preferences website we might be able to notice something that needs changed. Also if you look in the log (messages tab in Boinctasks) it may something like 'not requesting cpu tasks for ____ reason'. This is how mine are set currently on the Primegrid website -

 

[Markfw]

Thats it, The 8 and 1 are for the 12 different instanes on the 9654. It works good, as the 13th does CPU. Nothing uses school, work or Sun.

 

[Icecold]

You need to change this part here -

It's set to only run a max of 2 primegrid tasks for default and home, and 1 for mercury. It will only have that number of tasks total, regardless of whether they're CPU or GPU. You'll also see better points per day if you're running 2 or 4 cores (physical cores, not SMT) vs running 8 on these tasks. But your main issue is that you have the max # of simultaneous tasks set too low. I have mine set to unlimited.

 

[Markfw]

You need to change this part here - View attachment 120589

It's set to only run a max of 2 primegrid tasks for default and home, and 1 for mercury. It will only have that number of tasks total, regardless of whether they're CPU or GPU. You'll also see better points per day if you're running 2 or 4 cores (physical cores, not SMT) vs running 8 on these tasks. But your main issue is that you have the max # of simultaneous tasks set too low. I have mine set to unlimited.

Thanks. I restricted total tasks to simulate SMT off, and lasso did the rest. But adding CPU just hosed everything. I changed it, and will see after I get past the 2C tasks.

 

[cellarnoise]

What? We need to run more stuff! and NOW!

 

[Markfw]

What? We need to run more stuff! and NOW!

as a Team, we are murdering everyone. See the top 5 scores. more than 2nd+3rd, and soon I bet more than 1,2,3 put together, We have 2,5,6,9 in indiv users, I am 9th with no hope for any more. I might even turn off a couple. Why have AC running at 2:30 in the morning in my case. Its 86 in the house with everything wide open, and outside its 56F.

1​	TeAm AnandTech	16 913 590.97​	14 746​
2​	SETI.Germany	7 362 540.57​	7 451​
3​	Antarctic Crunchers	7 259 674.79​	6 099​
4​	BOINC.Italy	5 533 330.97​	3 895​
5​	AMD Users	4 368 455.59​	3 570​

 

[Icecold]

Thanks. I restricted total tasks to simulate SMT off, and lasso did the rest. But adding CPU just hosed everything. I changed it, and will see after I get past the 2C tasks.

I normally set BOINC to 'Use at most 50% of CPUs' for that. The Primegrid web site setting causes issues if you're trying to run CPU and GPU tasks on the same machine.

 

[Markfw]

After I found that lasso was not running correctly, I turned 3 back on. Only one off now. Went from 8 hours to less than an hour. Let see if I can get back a place or two.

Edit, and one video card was not running due to BOINC manager had GPU set to not run ! That was a 4080

 

[StefanR5R]

Out of curiosity, is anyone else who runs PrimeGrid on Windows (rather than on Linux) using Process Lasso also? And if so, does it offer an explicit "bind to last level cache domains" setting, or does the user have to come up with something else which yields the same effect?

A reminder of the most prominent alternatives on Windows:

• EPYCs and Threadrippers can be set to 1 CCX = 1 NUMA domain in the BIOS. Caveat: I don't know how effective Windows' NUMA handling is; this method works nicely with Linux at least.
• Computers with reasonably low amount of CCXs could run one BOINC client instance per CCX, with CPU affinity defined for the BOINC client process.
• Pavel Atnashev's AffinityWatcher (github link)
• pschoefer's Powershell script (SG forum, 2022 season thread, #535), perhaps with xii5ku's extras (SG forum, 2023 season thread, #485)

If I had a Windows computer at PrimeGrid or other projects which profit from CPU affinities, I would strongly gravitate to the last option in this list, somehow. :-)

I always split my CPU and GPU work between separate BOINC instances. The client is dumb

This is what I usually did too while I had a host with strong CPU and dGPU. (Right now I have a split of physical hosts for either CPU-only work, or for GPU work, but not both.)

If one really perfers to run CPU-only and GPU work in a single client instance, the PrimeGrid prefs hints from @Icecold are one thing. In general, not limited to PrimeGrid, one may have to resort to additional workarounds like an app_config.xml which pretends that the GPU app versions use near zero percent CPU. Still, the client will have its own mind of what to schedule when.

These stats update every 15 minutes or so - https://www.primegrid.com/challenge/2025_2/top_teams.html and https://www.primegrid.com/challenge/2025_2/top_users.html

Yes, update period is 15 minutes, as long as the server keeps up with the load. (It generally does.)
3rd party challenge stats:

https://www.seti-germany.de/pg_challenge/stats/​

https://statsgr.id/​

3rd party season stats:

https://www.rechenaugust.de/boinc/2025_Challenge_Series_Current_Standings_Teams.html​

https://www.rechenaugust.de/boinc/2025_Challenge_Series_Current_Standings_Individuals.html​