AMD Ryzen CPU Core Scaling Performance

[indepe]

Michael, you wrote "...Unfortunately it doesn't have an option for exposing eight cores without SMT (some Ryzen boards do offer an option to just outright disable SMT, but doesn't appear to be exposed with this current MSI BIOS) nor does it offer a "6 + 0" option....": This isn't possible because the 8 core Ryzen die consists of two 4 core parts. 6+0 would mean that the first part should have 6 of its 4 cores active, which isn't possible.

Why not, if 4+0, 3+0 and 2+0 are possible? 6+6 should also be possible if 3+3 is possible.

[juno]

@Michael: Agree with BlackArchon, you are looking at the CCX core setup, not the Cores and SMT for each. You can't disable SMT for each core, only enable or disable it entirely.

Why not, if 4+0, 3+0 and 2+0 are possible? 6+6 should also be possible if 3+3 is possible.

CCX = CPU CompleX, consisting of four cores with L2$ for each and shared L3$. Ryzen has two CCX.
With one CCX having four cores, 4+x or x+4 (with x <=4) is the maximum configuration.







Other reviews showed better performance for x+0 configuration instead of x/2 + x/2. That used to make sense, as data doesn't have to be transmitted in between the two CCX/L3$ pools (L3$ is still shared, so all cores have access, even the ones on the other CCX). However, some of Michael's benchmarks show the opposite, which is surprising.

I heard about a magic BIOS update that helps gaming performance

It's not magic, basically all the mainboard vendors screwed up their BIOS/UEFIs.
Looks like they underestimated Zen for too long and when they realised that there is money to be made, they rushed and pushed out crap.

[Adarion]

Interesting, very interesting. The "real" computing went as expected but holy cow at the Vulkan results with Dota. That issue should be inspected closely be developers of AMD firmware, Kernel, GPU driver and the game developers as well.

[devius]

...6+6 should also be possible if 3+3 is possible.

If it had 6 cores in each part then yes, but since it only has 4 you can't activate cores that don't exist. These options don't seem to be controlling SMT, but only the number of actual cores, so 4+4 is the max.

[indepe]

@Michael: Agree with BlackArchon, you are looking at the CCX core setup, not the Cores and SMT for each. You can't disable SMT for each core, only enable or disable it entirely.



CCX = CPU CompleX, consisting of four cores with L2$ for each and shared L3$. Ryzen has two CCX.
With one CCX having four cores, 4+x or x+4 (with x <=4) is the maximum configuration.

Then 3-0 actually is 6-0 in total ?

[caligula]

At least where SMT works, its amazing how well it scales

Of course it works. It's the mediocre code created by incompetent game developers that won't scale.

[BlackArchon]

Then 3-0 actually is 6-0 in total ?

3-0 means that there are three out of four cores from the first CCX active, while there are none active from the second CCX.

[juno]

Then 3-0 actually is 6-0 in total ?

If you are talking about threads, yeah, you're having 6 active threads.
Otherwise, no. 3-0 means 3-0. 3 active cores on one CCX and 0 more active ones on the other CCX, so 3 in total.

[Filiprino]

DOTA 2 and 3 cores are faster than Core i7 7700K with 4 cores.

[tomtomme]

Again, as two readers already stated above: michael got it all wrong. This bios setting he found is not about smt. Smt is allways enabled here. The setting is about the core count. Ryzen consists of 4+4cores