64 cores

Author	Message
mngn Send message Joined: 13 Jul 18 Posts: 38 Credit: 62,933,508 RAC: 84,702	Message 63611 - Posted: 8 Mar 2021, 16:38:27 UTC Is there any limit to the number of cores Boinc and CPDN can handle? I'm trying to justify the 64 core AMD Ryzen Threadripper 3990X for my next PC. https://www.amd.com/en/products/ryzen-threadripper ID: 63611 · Reply Quote

SolarSyonyk Send message Joined: 7 Sep 16 Posts: 262 Credit: 34,915,412 RAC: 16,463	Message 63613 - Posted: 8 Mar 2021, 16:53:44 UTC - in response to Message 63611. No reasonable limit to the number of cores, but CPDN is so cache heavy that you won't find great performance with that many threads - you'll just sit on your memory bandwidth limits. ID: 63613 · Reply Quote

Dave Jackson Volunteer moderator Send message Joined: 15 May 09 Posts: 4535 Credit: 18,966,742 RAC: 21,869	Message 63614 - Posted: 8 Mar 2021, 18:08:56 UTC - in response to Message 63611. Is there any limit to the number of cores Boinc and CPDN can handle? I'm trying to justify the 64 core AMD Ryzen Threadripper 3990X for my next PC. https://www.amd.com/en/products/ryzen-threadripper Depends on the mix of tasks, OS etc. HADAM4 N216 tasks use a lot of cache and if my memory is correct and the beast you are talking about has twice the level 3 cache of my 3700X then you will probably manage a maximum of about 16 without significant slow down as opposed to 8 for me. On Linux the hadcm3s are much more forgiving and I think the current windows tasks are also less demanding of level3cache. As I am sure you are aware, you will need a lot of RAM to avoid disk swapping. If I run 8 of the more demanding tasks, free ram drops to 1% with 32GB. I really need 64. Please do not private message myself or other moderators for help. This limits the number of people who are able to help and deprives others who may benefit from the answer. ID: 63614 · Reply Quote

mngn Send message Joined: 13 Jul 18 Posts: 38 Credit: 62,933,508 RAC: 84,702	Message 63616 - Posted: 8 Mar 2021, 18:34:38 UTC - in response to Message 63614. Last modified: 8 Mar 2021, 18:46:27 UTC The 3990X has 256MB L3 cache and the 3700X has 32MB L3 cache. So eight times eight tasks makes running 64 tasks possible. Lots of writes to disk though. I expect to use 256GB of RAM, 4GB per task. Might be too little. ID: 63616 · Reply Quote

Les Bayliss Volunteer moderator Send message Joined: 5 Sep 04 Posts: 7629 Credit: 24,240,330 RAC: 0	Message 63625 - Posted: 8 Mar 2021, 20:52:17 UTC - in response to Message 63611. Try it and see. We need more guinea pigs. :) ID: 63625 · Reply Quote

Dave Jackson Volunteer moderator Send message Joined: 15 May 09 Posts: 4535 Credit: 18,966,742 RAC: 21,869	Message 63627 - Posted: 8 Mar 2021, 22:07:10 UTC - in response to Message 63616. I expect to use 256GB of RAM, 4GB per task. Might be too little. I find 32GB too little for running 8 N216 tasks though an M2 drive which swap is on reduces the performance hit. Before too much longer I will be going up to 64GB Please do not private message myself or other moderators for help. This limits the number of people who are able to help and deprives others who may benefit from the answer. ID: 63627 · Reply Quote

KAMasud Send message Joined: 6 Oct 06 Posts: 204 Credit: 7,608,986 RAC: 0	Message 63643 - Posted: 10 Mar 2021, 4:37:37 UTC I live in a very Arid and hot part of South Asia. With great difficulty due to the temperature of the system rising I can run three threads at most out of twelve. Then there is this little problem of RAM. I wonder what will happen if I run a 64 core flat out? Maybe a sound of things going drip, drip. ID: 63643 · Reply Quote