Primegrid Challenge Series 2026

[StefanR5R]

This challenge happens at PrimeGrid's "FPS" project. From the sound of it, I expect The FPS Team to do well in this challenge, otherwise I would be thoroughly confused.

estimated average of 45 hours per task

This is the average CPU time of recently returned results. Task duration is correspondingly less than this if multithreading is used. E.g. roughly half of this if 2-threaded, and so on.

Estimated cache footprint of recent tasks is 10 MBytes. Therefore, multithreading is recommended, based on the ratio of core count to last level cache size of your particular CPUs. E.g. those AMD CPUs which have 32 MB sized core complexes should probably run no more than two tasks at once on each core complex, and dedicate half of the physical cores of a CCX to each task.

(Squeezing three tasks at once onto such a CCX might work too, perhaps with some SMT usage even, but this should better be tested individually for a given host and given socket power settings. Besides, while throughput is the main goal of optimization for such a challenge, task durations should also be kept in check for better chances of getting some more tasks finished right before the end of a challenge.)

 

[Skillz]

I'll have to run two per CCD on most of my hardware since it's still mostly Zen2 with 16MB CCX. Might have 32MB per CCD, but since it's split between two CCX with 16MB each I'm not sure running 3x in a CCD will be better due to the infinite fabric speeds being a bit slower.

I'll try to get some benchmarks up sometime late this week when I get home.

 

[StefanR5R]

Sure, if the CCXs have only 16 MB L3$, one task per CCX it is.

With Zen 2 server (and desktop), cross-CCX traffic between CCXs of the same CCD is just as costly as traffic between CCXs of different CCDs. Should be avoided either way in case of PrimeGrid's PRST application.

 

[OrangeKid]

On my machines at least, I have found that 2x8 is slightly better than 4x4.
Affinity on with no smt.

 

[Icecold]

The challenge starts in an hour and 40 minutes, I hope everybody's ready!

@OrangeKid I have noticed the same on my Ryzens

 

[Icecold]

It has now started

 

[Skillz]

I'm at work, but I'll be firing up the fleet when I get home.

User rankings: https://www.primegrid.com/challenge/2026_4/top_users.html


Team rankings: https://www.primegrid.com/challenge/2026_4/top_teams.html

 

[StefanR5R]

Estimated cache footprint of recent tasks is 10 MBytes. [...] Squeezing three tasks at once onto [a CCX with 32 MB] might work too,

Cache footprint of some workunits is now 12 MB already, therefore best leave it at no more than 2 tasks at once per 32 MB cache segment (if you have this kind of CPUs).

 

[Skillz]

or in my case, since most of my CPUs are still Zen2. It'll be the same as if it were still 10MB requirements since each CCD is divided into two CCX's each with 16MB L3.

 

[Skillz]

I know we got people on here with some nice CPUs they can help us with. Currently in 2nd place.

 

[Skillz]

@David_Schroth you going to throw a CPU at this challenge for us?

 

[David_Schroth]

@David_Schroth you going to throw a CPU at this challenge for us?

Tossed on a Xeon with your assistance!

 

[Skillz]

Tossed on a Xeon with your assistance!

Welcome to the team!

If anyone else needs help. Feel free to ask.

 

[OrangeKid]

Welcome to the fray.
You will now spend all your extra money on more and more computer hardware.
Become enamored in amassing more points than the next person.
Good luck and thanks.

 

[Icecold]

I have a feeling the 9:45PM E/T Primegrid update will be interesting

 

[Skillz]

Daaaang that's a massive bunker! Got worried about the power outage yesterday?

 

[Icecold]

Daaaang that's a massive bunker! Got worried about the power outage yesterday?

Somewhat but more so the challenge was getting kind of boring and tasks were getting close to the deadline listed in boinc manager (I think they have a 24 hour grace period though based on what the tasks on the website show). It was either release some bunkers as necessary or just release everything. I opted for the release everything and made sure to do it so all 32.5 million points made it into one stats update

 

[Skillz]

It was a beautiful drop no doubt.

 

[OrangeKid]

Congrats Icecold on 1st place and a 1st for the team.
Great run all.

 

[Skillz]

Yep, congrats everyone.

Here is the more-or-less final member totals.

Team   Name           Points      Overall
  1    Icecold        49,981,605      1
  2    cellarnoise2   22,514,504      6
  3    Skillz         20,336,164      7
  4    crashtech      16,463,997      8
  5    w a h           7,182,549     24
  6    Orange Kid      5,783,970     28
  7    biodoc          3,830,444     32
  8    Werinbert       2,521,414     50
  9    mmonnin         2,439,832     51
 10    Schro           1,440,036     77

and the top 10 teams

Rank  Team                   Points     Tasks
  1   The FPS Team       132,494,515    7,325
  2   Czech National Team 73,884,217    5,960
  3   BOINC@AUSTRALIA     67,630,901    3,765
  4   SETI.Germany        51,009,278    3,690
  5   Antarctic Crunchers 44,216,950    3,291
  6   Romania             35,750,673    2,009
  7   Aggie The Pew       30,012,108    1,730
  8   Ukraine             26,208,273    2,385
  9   TeAm AnandTech      17,219,568      971
 10   BOINC@MIXI          16,442,466    1,542

Due to the time of the challenge I wasn't able to do daily updates. Really need to write some scripts to automate this for me.