Ryzen 5 and SMT

Binder · December 29, 2017

so, i have a ryzen 5 1600 and since i basically game for 99% of the time i get to use my pc (well that and netflix) i decided to play with the SMT setting a bit to see how much i actually gain in games, plus if i can push my oc slightly higher.

so i disabled SMT, kept the same settings exactly as they were (same vcore ,soc etc) and just upped the cpu frequency from 3.9 to 3.95 ( 3.95 used to crash on prime, so i wanted to see if it holds now with SMT OFF).

to my surprise, even though i read everywhere that temps with SMT OFF should be lower, they were actually higher, and not just that, they rose much quicker (time wise). it reached a point where i stopped the test because it started to quickly surpass 70 and didn't show a sign of stopping...this is weird as with SMT on, there is a much slower temp rise as well as a lower max temp in general.
anyone care to explain? thanks.

Energycore · December 29, 2017

Well for one, you can keep going up in temps to 85C without danger, so you can test how much higher are the temps.

The increased temperature from SMT off might be due to a voltage increase somehow, if you have voltage at auto and increased the clocks then it would have upped the voltage sometimes by a significant amount. But it sounds like you input manual voltage so I'm not sure.

Binder · December 29, 2017

Nope, manual voltage indeed, 1.385v with llc 2, have been running and tested for months, I changed nothing besides the frequency (multiplier) and turned off smt. Thats why its so weird. I know it can go up to the higher 80's without danger , but since with smt on it never passes 70-71, I didn't see a point in continuing.

This is just strange. I'm really curious why this is happening. I put it back on smt enabled and the temps went to be normal again....that's really the only variable that changed.