Question SMT amd cpu's multi threading

bilakoc213

Commendable
Feb 27, 2019
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i always have been wondering and trying to understand how things works with smt correct me if i'm wrong i've seen people turning off smt and they have better expeience in games because they dont really want multi threading i think smt is more for like multi tasking editing videos something like that but what happens when you disable smt play a game and while the game is on at the same time you multi task does that make things worse than having it on?
 
i always have been wondering and trying to understand how things works with smt correct me if i'm wrong i've seen people turning off smt and they have better expeience in games because they dont really want multi threading i think smt is more for like multi tasking editing videos something like that but what happens when you disable smt play a game and while the game is on at the same time you multi task does that make things worse than having it on?
SMT is a hardware trick that tells the operating system there is more CPU resources than there really is. SO, if you have a 4C/8T CPU you can enable SMT and have the OS "think" there are 8 parallel execution paths or you can disable SMT and the OS "thinks" there are 4.
If you have a game that can fully use 4 simultaneous execution paths, then trying to do something else at the same time, takes resources away from the game. If you have SMT on the OS will schedule a 5th simultaneous execution thread (your multitasking). That STILL has to take resources away from the game because there are still on 4 physical cores. BUT the CPU can switch between the 5 threads faster than it can when SMT is disabled because the CPU has to do more work between active threads without SMT. Will having SMT on, prevent the game from being impacted? Unknown. The game wants 100% of 4 physical cores. Anything less degrades performance some amount. How much degradation is dependent on memory bandwidth and GPU performance and even your reflexes.
 
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