AMD FX 8350 being detected as a 4 core CPU

dfj2000 · May 31, 2014

So my FX 8350 is being detected as a 4 core CPU, but that has 8 threads. Should i take this with a grain of salt as not a big deal, or should I change something? I'm using windows 8.

Here's what my task manager states:
http://postimg.org/image/xgvhz1dy1/

Nordein · May 31, 2014

Well then..that is a bit odd. I would suggest try updating your drivers or reverting to an older one. If that does not work maybe check in your bios screen to see if anything funky is going on.

CodenameHaswell · May 31, 2014

I read this somewhere on TomsHardware forums.

"The AMD FX-8350 has 4 modules with 2 cores in each module. Each 2 cores in the module will share resources. Yes, there are 8 cores in total, but they are not separate, and are not hyper-threading. This is a good cost saver for AMD.
Intel quad-core CPUs will have 4 modules with a core in each module."

I would take it as a grain of salt, it says you have 8 logical cores, I'm assuming that the 4 modules have 2 cores, and windows only recognises the modules. I would only worry if you see any degrading in performance.

ingtar33 · May 31, 2014

ignore windows... it's stupid... and either coded incompetently or paid off by intel. Either way sometimes windows detects 8 core fx cpus as 8 core, sometimes as 4 with 8 threads. My fx8320 is detected in windows 7 sp 1 as an 8 core... though i might have downloaded an optional windows update that made it detect it right. I don't recall. but i know windows 7 (no sp) and windows 8 (no sp, no 8.1) WILL detect the fx 8 cores as quad cores for reasons unknown. Never heard of it treating the 6 or 4 core fx like this, just the 8 core.

EpiclyDelicious · May 31, 2014

The FX-8350 isn't a technically an eight-core processor. It is, but not in the sense that you think. It's four real cores with 1 "virtual" core on each real core I believe. I'm not good at explaining it, but that's the best explanation of what I know, or think.

This is why the FX-8350 isn't too good at single-core performance.

ingtar33 · May 31, 2014

EpiclyDelicious :

This post is completely 100% wrong.

I'm going to copy and paste my own post on another forum explaining this one more time...

Now then, onto the topic of the bulldozer cpu architecture. Some intel fanboys like to make the claim its a type of "hyperthreading" and not a true "8/6/4" core cpu. I suppose i can sorta see their point of view but like most fanboy arguments it's based on a lack of understanding or just pure sophistry.

The engineering definition of a cpu "core" is that a core must have 3 parts
1) instruction control unit
2) instruction execution unit
3) input/ouput unit

AMD's bulldozer family cpu cores have all of these parts; each core module contains 2 separate cores, each one of those cores has their their own scheduler (control unit), 4 execution units, and an I/O unit.

The confusion about the bulldozer architecture, comes from the floating point processor unit. You see up until 2000 or so, no cpu had a floating point processor. In fact computers around 1997 started to include math-coprocessors add on boards to handle the floating point math... around 2000 cpus started to integrate the math coprocessor, called a floating point processor onto the cpu itself. These units basically handle floating point math (calculus) which traditional cpus rather suck at. Now understand, these floating point processors are completely separate units from the cpu core on both an AMD and Intel cpu... in a way they're sorta the progenitor to the whole concept of an APU, as all a gpu really is, is a highly specialized math coprocessor or calculus calculator. AMD chose, with bulldozer, to place 1 256-bit floating point processors on their cpu per core module... that single FPU is naturally a 256-bit unit, but when needed can function like 2 128 bit FPUs, THIS is the part that works like a gimped version of intel's hyperthreading; as in it's a single FPU which can at times, when needed handle 2 instructions at the same time.

The fx cpus ARE by every definition proper 4/6/8 core cpus. They just work a little different with their design then an intel cpu... or even the older retired AMD k10 architecture; with bulldozer AMD went modular, it's intention was to make a chip they could easily customize for server environments, and any other "unique" environments they may be requested by a client to match. Its actually because of the highly modular design of bulldozer that AMD landed the 2 next gen consoles... it simply was cheaper and easier to make a custom chip for both M$ and Sony then it was for anyone else to do. Its also because of this modular and unfocused design that bulldozer/piledriver/steamroller simply can't compete in performance with intel's highly specialized performance cpu lines.

EpiclyDelicious · May 31, 2014

ingtar33 :

Well due to my ignorance on the matter does not warrant calling me an "intel fanboy."

But when you're trying to explain this to someone, it makes absolutely zero sense due to jargon and no outside knowledge of the history of processors. Why not summarize what you said so it's easier to read?

I do agree what I said was incorrect. I did some research, as I should have done before posting, and found out something. What I typed had some typos in it. I meant to say "2 virtual cores," even though that's still incorrect.

Someone here mentioned modules. The FX-8350 has eight cores/4 modules. Each module has 2 cores in it. The resources are shared between those two cores. (As I've read.) The two cores per each module are not separate, that's why "intel fanboys" or some ignorant people tend to believe it's only four core. Either way, this processor has less single-core performance than some Intel processors, which is obvious. (Not an Intel fanboy if I must say so again.) I believe performance is bottlenecked (specificaly in single-core) because of the FPU (Floating Point Unit) which causes one core to "wait" for the other core to finish using it.

Am I correct? Or wrong? I'm happy to accept I am wrong and figure out what is correct.

vmN · May 31, 2014

The bulldozer family are running an core technology called CMT. Intel is running with SMT (Hyper-threading).

CMT is basically duplication certain parts in an core. In this case we are talking about the integer and memory pipelines (Steamroller duplicated the decoders aswell, one of the few improvement over piledriver).

The FX 8350 feature 4 CMT cores. AMD calls an CMT core a module.

There are no real definition of an core. I like to think an real physical core needs its own frontend and backend for it self.

The cores in these modules share the entire frontend (Steamroller added decoders, but still share things like the fetch and BP).
The cores also share the SIMD (In this case 2 MMX and 2 128bit FMAC). Excavator will add more SIMD hardware.

CMT is in use to be space-efficient.

CMT isn't the total reason why it can't compete with Intels counterpart.

ingtar33 · May 31, 2014

Sorry, I did not mean to say you were a fanboy. As I stated in my post I was quoting from a separate forum post, the discussion at the time had a number of fanboys arguing at the time saying silly stuff. I probably should have edited out the comments about fanboys but I was distracted and in a rush.

As to the claim there is no definition of a CPU core. That is also wrong. I just gave you the engineering definition. Yes the share resources, that's part of the modular design. It's a good design it just suffers from a lot of power 'bleed', as a result it simply doesn't scale in performance well.

EpiclyDelicious · May 31, 2014

ingtar33 :

Quite alright. We all have those times. I simply respect your information as you not only have the CPU Master Badge I believe, but you definitely seem to know what you're talking about.

Glad I learned something today. :]

vmN · May 31, 2014

Do you have any kind of validation that that is engineering definition of a core?

Also I wouldn't really call an ALU an core, as you mentioned.

Piledriver simply suffer, because of the execution unit per core is low compared to Intels.

Haswell have 4 ALUs per core whereof Piledriver have 4 ALUs per module (2 ALUs for each "core").
And not even to mention SIMD...

JOOK-D · May 31, 2014

You could always try a BIOS update.

These are also available. People have had varying performance increases from using them:

Core unparking.
http://bitsum.com/about_cpu_core_parking.php

Windows hotfixes:
http://support.microsoft.com/kb/2646060
http://support.microsoft.com/kb/2645594

ingtar33 · May 31, 2014

vmN :

Well, i was quoting an engineer i know who works at intel here in phoenix, but since you asked i looked it up, and on the wiki we find under "microarchitecture" this definition of a core's instruction cycle...

1) Read an instruction and decode it
2) Find any associated data that is needed to process the instruction
3) Process the instruction
4) Write the results out

number 2 is the control unit in my definition; number 3 of course would be the execution unit, and 1&4 would be the I/O unit; when you step beyond wiki as i just did, i find almost every definition of a "core" contains those 4 elements, including the one i posted. And on a piledriver/bulldozer/steamroller cpu all the "named" cores contain those parts, unshared with the rest of the architecture.

You're right, the integer cores (two per module) have 2 ALUs per core, or 4 per module, they also have 2 AGUs per core or 4 per module, all together they have 4 Execution Units per core. Not sure the point you're trying to make.

That said a haswell has 4 ALUs and 3 AGUs per core, while ivybridge only had 3 and 2 of each per core. Using the NUMBER of ALUs and AGUs to define a core is questionable to say the least, as it has no relation to number of cores, simply the core design. the smaller process node haswell is made on allowed intel to add more ALUs and AGUs per core then existed in previous intel chips. Most chips, dating back to the p4 had 2 ALUs per core... as does piledriver/bulldozer/steamroller.

as you can see adding 33% more ALUs and 50% more AGUs did not increase haswell's core performance significantly over ivy bridge... the ALUs and AGUs only have a tenius relationship to cpu core performance.

vmN · May 31, 2014

I would wonder how an x86 core would perform without its fetch. Also piledriver share their decoders.

Can we please stop calling EUs for cores? They are not. I never implied they were.

Haswell can have much higher core performance than IVY, simply about utilizing the ISA correctly. Haswell do also have superior integer performance.

vmN · May 31, 2014

Just to be clear

Number 1 is the decoders
Number 2 is the fetch
Number 3 is the EUs
Number 4 is the I/O pipeline.

Piledriver cores in the module is sharing the fetch and decoders.

psiboy · Aug 14, 2015

EpiclyDelicious :

Sorry ED You are completely wrong!

stephan_daigle · Oct 12, 2017

run>msconfig>boot>advanced options>unchecked the number of processors box ; worked for me

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