Why does disabling cores and/or hyper-threading disable S3

[technicianadvance]

Why does disabling cores and/or hyper-threading disable S3? I just found out that Lost Planet 2 can only run on computers with at most 6 cores. But my motherboard says that S3 will be disabled if I disable cores or hyper-threading. I have the Asrock B450M pro4 and the Ryzen 7 2700. Does anyone know why this happens?  I just want to play the game and have my computer sleep but my computer cannot sleep without S3.

[Streetguru]

27 minutes ago, dlscientist said:

Why does disabling cores and/or hyper-threading disable S3? I just found out that Lost Planet 2 can only run on computers with at most 6 cores. But my motherboard says that S3 will be disabled if I disable cores or hyper-threading. I have the Asrock B450M pro4 and the Ryzen 7 2700. Does anyone know why this happens?  I just want to play the game and have my computer sleep but my computer cannot sleep without S3.

Just disable it anyways and see what happens?

Or go down to 3 cores  6 threads or something if possible.

 

Very strange bug for a game

[technicianadvance]

3 hours ago, Streetguru said:

Just disable it anyways and see what happens?

Or go down to 3 cores  6 threads or something if possible.

 

Very strange bug for a game

So I did it and the manual was correct. I disabled 2 cores. I can no longer go into the S3 state and sleep. But I can now play Lost Planet 2. Any CPU or motherboard engineers out there that can explain why disabling cores disables the S3 power state?

[Mark Kaine]

I would like to know this as well. 

I do not understand such restrictive behavior,  I would assume a design mistake somewhere in the development phase,  but maybe there are actual physical limitations or some such? 

[technicianadvance]

On 11/10/2019 at 11:41 PM, Mark Kaine said:

I would like to know this as well. 

I do not understand such restrictive behavior,  I would assume a design mistake somewhere in the development phase,  but maybe there are actual physical limitations or some such? 

Does anyone know any AMD AM4 boards  that will let you disable cores without disabling S3 (sleep)?

[MiamiMichael]

It has to do with the precision timing used for SMT and the design of the CPU.

There is no way around it as of Zen 4