AMD Ryzen CPU

[Vinkman]

Pudgie,
When using affinity in Windows 7 on my Ryzen chip it shows 16 cores not 8. I'm wondering why that is. 

[Pudgie]

Pudgie,
When using affinity in Windows 7 on my Ryzen chip it shows 16 cores not 8. I'm wondering why that is. 

Hi Vinkman,
You are seeing the 1800X CPU's 16 logical cores due to SMT being enabled (when SMT is enabled, it creates 2 logical CPU cores for every 1 physical CPU core in which the 2 logical CPU cores are made to look like real CPU cores to Windows OS in every aspect structurally).

SMT (simultaneous multitasking.....similar to Intel's hyperthreading or HT).       

 

[Pudgie]

When using CPU affinity w/ this AMD Ryzen 1800X CPU you will need to know & understand the binary numbering order of these cores, whether SMT is enabled or not but more important to know this w/ SMT enabled.

Windows usually numbers these CPU cores from right to left starting w/ the number "0" as the 1st CPU core w/ core1 being the 2nd logical CPU core that represents the physical CPU core 0.

This is why the latency looks so good when threads are shown to be switching between the 2 logical cores that are tied to the single physical CPU core as in reality it's the SAME CPU core.

Assigning CPU core affinity is much easier to do when SMT (or HT Intel CPU's) is disabled as then ALL available CPU cores are the real ones.

Then you will need to figure out where the number groups fit within the CPU CCX modules so that you can assign a process to the CPU cores within a CCX so that you can reduce/eliminate the thread switching across CPU cores that are located in separate CCX's.

Will need to find a CCX core mapping that will show this numbering........

If I do find 1 I'll post it............

Hope this helps you out.

 

SMT (or HT) was originally designed to optimize "multi threading" across a single CPU core by allowing a 2nd thread to use the idle CPU core time created from the 1st thread being stalled waiting on other data to be made available for the CPU core can finish processing the 1st thread. This worked well for Intel when the consumer CPU consisted of a single CPU core on die. Once the CPU core counts exceed a certain number the validity of SMT vanishes EXCEPT only in a case where the process(s) can generate enough threads to fully saturate ALL the CPU cores.........which for the majority of consumers usage will never reach this level. From all my testing, once you reach 4 physical CPU cores the validity of SMT (or HT) drops off & Windows is coded to automatically "park" 1/2 of the logical CPU cores when the thread loads aren't sufficient to justify using them so in essence Windows just "disabled" SMT (or HT on Intel CPU's) & is in reality only using the real physical CPU cores..........
This is why I say that when more than 4 CPU cores are being used SMT (or HT) is a red herring  most consumer usage levels & is oversold by all......overhyped..........

IMHO of course.........

 

[flyndung]

you think that's good check out this http://www.tweaktown.com/news/56845/amds-high-end-x390-x399-mobo-dual-ryzen-cpus-possible/index.html , dual ryzen Motherboard

[Vinkman]

When using CPU affinity w/ this AMD Ryzen 1800X CPU you will need to know & understand the binary numbering order of these cores, whether SMT is enabled or not but more important to know this w/ SMT enabled.

Windows usually numbers these CPU cores from right to left starting w/ the number "0" as the 1st CPU core w/ core1 being the 2nd logical CPU core that represents the physical CPU core 0.

This is why the latency looks so good when threads are shown to be switching between the 2 logical cores that are tied to the single physical CPU core as in reality it's the SAME CPU core.

Assigning CPU core affinity is much easier to do when SMT (or HT Intel CPU's) is disabled as then ALL available CPU cores are the real ones.

Then you will need to figure out where the number groups fit within the CPU CCX modules so that you can assign a process to the CPU cores within a CCX so that you can reduce/eliminate the thread switching across CPU cores that are located in separate CCX's.

Will need to find a CCX core mapping that will show this numbering........

If I do find 1 I'll post it............

Hope this helps you out.

 

SMT (or HT) was originally designed to optimize "multi threading" across a single CPU core by allowing a 2nd thread to use the idle CPU core time created from the 1st thread being stalled waiting on other data to be made available for the CPU core can finish processing the 1st thread. This worked well for Intel when the consumer CPU consisted of a single CPU core on die. Once the CPU core counts exceed a certain number the validity of SMT vanishes EXCEPT only in a case where the process(s) can generate enough threads to fully saturate ALL the CPU cores.........which for the majority of consumers usage will never reach this level. From all my testing, once you reach 4 physical CPU cores the validity of SMT (or HT) drops off & Windows is coded to automatically "park" 1/2 of the logical CPU cores when the thread loads aren't sufficient to justify using them so in essence Windows just "disabled" SMT (or HT on Intel CPU's) & is in reality only using the real physical CPU cores..........
This is why I say that when more than 4 CPU cores are being used SMT (or HT) is a red herring  most consumer usage levels & is oversold by all......overhyped..........

IMHO of course.........

 

As always, good info Pudgie. I'd like to check out your theory, by disabling SMT and seeing if the # of cores drops back to 8. how does one deactive/active SMT?

[Pudgie]

As always, good info Pudgie. I'd like to check out your theory, by disabling SMT and seeing if the # of cores drops back to 8. how does one deactive/active SMT?

For certain this can be done thru thru the mobo's UEFI (or BIOS if you prefer), which is where I would do it.
With AMD's Ryzen Master UEFI interface, there may be a setting to do this there as well but not sure of this as I don't own 1 of these yet.

 

[Vinkman]

For certain this can be done thru thru the mobo's UEFI (or BIOS if you prefer), which is where I would do it.
With AMD's Ryzen Master UEFI interface, there may be a setting to do this there as well but not sure of this as I don't own 1 of these yet.

 

OK I will look up how to do it. 

[Pudgie]

Here is a block diagram of an AMD AM4 mobo layout provided by MSI that shows some design features of the AM4 socket that I wasn't aware of.
This is using an X370 chipset:

http://imgur.com/a/Xl4gN

I've looked all over the Internet to see if anyone else (Asus, Gigabyte, ASRock, Biostar, etc.) has posted anything similar to see if this is more or less a common board layout or is specific to MSI......to date I've found none.

If this is indicative, it will matter somewhat which USB ports certain devices are plugged in, which PCI-E lanes certain devices are plugged into, etc when device performance or overall system performance is concerned.....at least when using a MSI AMD AM4 X370-equipped mobo.

I for 1 would love to see that this MSI block diagram, especially concerning the CPU socket layout, is the standard layout for all AM4 mobos. If going by the AMD 7th-generation APU block diagram CPU socket layout as a guide, it should be.

FYI.......................... .

 

[Vinkman]

Hi Vinkman,
You are seeing the 1800X CPU's 16 logical cores due to SMT being enabled (when SMT is enabled, it creates 2 logical CPU cores for every 1 physical CPU core in which the 2 logical CPU cores are made to look like real CPU cores to Windows OS in every aspect structurally).

SMT (simultaneous multitasking.....similar to Intel's hyperthreading or HT).       

 

I've been playing around with it and I have not figured out how to turn that off yet.

[Vinkman]

Just some updates...

I did find that in heavy traffic I was getting FR decreases after the board discussion on Memory speeds I looked what my machine was running at. Even though I had 32 Gig of DDR4 2400 @16 CASL, the base speed was 1200 Mhz. I used the Mobo UEFI to test clock speed increases and the highest I could get it was 2133Mhz.

This make a huge improvement in frame rate in high traffic, and with frame rate drops/stutters over towns and other building intense areas.

Next I tried 16Gig off DDR4 3200 @ 14 CASL. This could achieve a clock speed of 2400Mhz. This set up seems no different than the above.

The Ryzen set is set for a constant 3.85GHz and is liquid cooled running at an indicated 58-63c.

With this setup I am achieve 60 FR (vsynched) with the following Video settings....
Max Texture size 4060
Anti-aliasing X12 Edge Detect [using the ATI Gaming settings]

Object detail Slider = MAX
Terrain Detail Slider = MAX
Tree Detail Slider = 50%
Ground Range = MAX (3 Miles)
Environment slider = None.

Other Plane Skins Enabled
Shadows Disabled
Ground Clutter in Flight Disabled
Bump Mapping Enabled
Detail Enabled
Reflection Enabled
Post lighting All Enabled

Still can;t run shadows because that's a loss of 30 Frames/sec. I can run all sides in the environment map for the reflections but   I lose 12Fr/sec and run 48Fr/sec which doesn't look smooth enough to me. I can run 2 sides at 60Fr/sec but the reflected view stutters and it doesn't look right.


There are still stutters that are usually caused by objects caching. It seems as new planes. smoke, buildings or building damage come in and out of field [only when the count is high] there is a momentary freeze while an object caches.

the Vid mem is showing 900-1100K of use, but my card has 2Gig of RAM so the mem size seems fine.

So now I'm wondering what the current cork in the bottle is.  My memory clock speed on vid card is only 1Gig. But I'm wondering if this is still a system memory speed issue.

I'll keep fiddling. 

[Bruv119]

if you only have a 2gig card that is your issue.

i have 8gb ram 6gb card and it runs everything max.

[Skuzzy]

2GB should be enough for 1080p, if the GPU is fast enough.

[Vinkman]

2GB should be enough for 1080p, if the GPU is fast enough.

GPU is glocked at 750MHz

[Skuzzy]

Clock rate is not relevant.  What model GPU?

[Vinkman]

Clock rate is not relevant.  What model GPU?

ATI Radeon 5970.