The AMD FX-8350 is not a true Octacore CPU.

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NoasArcAngel

Wise Old Owl
Piledriver is still based on the same basic design as Bulldozer, with the ‘8-core’ chip containing four Piledriver modules, each of which contains a pair of integer cores. While AMD markets these as individual CPU cores, each module’s pair of integer cores shares a number of resources, including the fetch and decode units, a Floating Point scheduler (FPU) and 2MB of L2 cache. This is part of AMD’s design philosophy of focusing on multi-threaded performance, with each module able to process two threads simultaneously. As we found last year though, this comes at the cost of single-threaded performance and with the down-side that relatively few applications are able to make use of four cores in multi-threaded workloads, let alone eight

piledriver-3s.jpg


AMD FX-8350 review | bit-tech.net

read more here : http://www.thinkdigit.com/forum/pc-...ew-gaming-pc-config-suggestions-advice-2.html
 

Hrishi

******************
Same goes with their Apus like a10-4600m which is not a true quad design but is being marketed as quad core.
 
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NoasArcAngel

NoasArcAngel

Wise Old Owl
What's the problem if the chip performs well? In many tasks the fx 8350 is very close to i7 3770k which is almost double the price of fx 8350.

thats whats wrong, its only in some tasks... tasks which suit a quadcore that the fx8350 outperforms the i7, but for other practical purposes like gaming its pretty much useless.
 

hitesh

In the zone
Thanks @Noasarcangel for posting. I was thinking of posting something like this too but damn I'm too lazy.
It is very wrong of AMD to advertize this as 8 core cpu :-(

and when we suggest configs, everyone drools over the fx8350, best VFM option and this and that. :|

Exactly. They just go with this 8 core thing and the best value for money and stuff like that !
They don't even bother to look at benchmarks :-?
 

Cilus

laborare est orare
Buddy, we all here know that neither Bulldozer, nor Piledriver, are tru OctaCore CPU and in fact we do have some great articles here, written by the forum members, explaining the details of the Module based architecture.

And some information about Piledriver: Currently each of the BD/PD modules has a Dual Fetch Unit (Fetch Unit fetches data and instructions from Main Memory or CPU registers) but a single Decode Unit (Decode Unit decodes the Assembly language to CPU understandable Binary Code). As a result there is a bottleneck in instruction decoding for a particular thread. Theoretically, two Integer Cores of a BD/PD module can work on the instructions of a single thread. But it is observed that a single Decoding unit is not able to decode instructions/Data in such a rate to properly feed the two Cores.
So in Steam Roller design, each of the two Integer Cores of a module will have a dedicated Decoding Unit, one per Core, to eliminate the bottleneck and increase both IPS and TLP.

Regarding share L2 Cache, it is actually a good move. Sharing L2 Cache actually increases the Cache usage efficiency. Because if you use Static Cache Partition, say 1 MB dedicated for each of the Cores of a Module, then when one Core is not using the Cache and it is empty, it cannot be allocated for the 2nd Core which is having high CPU load and multiple memory access. On the other hand, if you have dynamically allocated Cache Partition, then while the Cache is empty or not allocated for 1 Core, the 2nd Core can take advantage of full 2 MB Cache.
 
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NoasArcAngel

NoasArcAngel

Wise Old Owl
Buddy, we all here know that neither Bulldozer, nor Piledriver, are tru OctaCore CPU and in fact we do have some great articles here, written by the forum members, explaining the details of the Module based architecture.

And some information about Piledriver: Currently each of the BD/PD modules has a Dual Fetch Unit (Fetch Unit fetches data and instructions from Main Memory or CPU registers) but a single Decode Unit (Decode Unit decodes the Assembly language to CPU understandable Binary Code). As a result there is a bottleneck in instruction decoding for a particular thread. Theoretically, two Integer Cores of a BD/PD module can work on the instructions of a single thread. But it is observed that a single Decoding unit is not able to decode instructions/Data in such a rate to properly feed the two Cores.
So in Steam Roller design, each of the two Integer Cores of a module will have a dedicated Decoding Unit, one per Core, to eliminate the bottleneck and increase both IPS and TLP.

Regarding share L2 Cache, it is actually a good move. Sharing L2 Cache actually increases the Cache usage efficiency. Because if you use Static Cache Partition, say 1 MB dedicated for each of the Cores of a Module, then when one Core is not using the Cache and it is empty, it cannot be allocated for the 2nd Core which is having high CPU load and multiple memory access. On the other hand, if you have dynamically allocated Cache Partition, then while the Cache is empty or not allocated for 1 Core, the 2nd Core can take advantage of full 2 MB Cache.

thanks for the explanation, if you already know that then why do you suggest that the fx 8350 is a processor of the future?
 

Cilus

laborare est orare
Because performance per dollar ratio is far higher with FX-8350. For an end user, it does not matter whether it is a true 8 Core or not, for him, performance/Dollar ratio matters more. Last time, when I tried to explain, we got into some heated argument, leading to personal attacks. If you can keep your head cool, I can try to explain a little.

Also, I think you know that the poor performance of BD and PD are also attributed to the improper thread scheduling of Windows OS, it is not a hardware design fault all the time. In most of the Linux builds which have very good and optimized CPU thread management methods, both Bulldozer and PileDriver Flagship CPUs perform very closer to i7 2600K and i7 3770K, while offering far lesser price.

I am not at all any Fan Boy as you guys are thinking but I know a little bit of Computer Architecture and Game design. I have a good idea about how things work inside a CPU. If you can have a little patience then long back I have written article about BD design and its poor performance in Windows 7 environment. You can have a look:
http://www.thinkdigit.com/forum/cpu...n-poor-performance-bulldozer-windows-7-a.html
 

Hrishi

******************
Because performance per dollar ratio is far higher with FX-8350. For an end user, it does not matter whether it is a true 8 Core or not, for him, performance/Dollar ratio matters more. Last time, when I tried to explain, we got into some heated argument, leading to personal attacks. If you can keep your head cool, I can try to explain a little.

Also, I think you know that the poor performance of BD and PD are also attributed to the improper thread scheduling of Windows OS, it is not a hardware design fault all the time. In most of the Linux builds which have very good and optimized CPU thread management methods, both Bulldozer and PileDriver Flagship CPUs perform very closer to i7 2600K and i7 3770K, while offering far lesser price.

I am not at all any Fan Boy as you guys are thinking but I know a little bit of Computer Architecture and Game design. I have a good idea about how things work inside a CPU. If you can have a little patience then long back I have written article about BD design and its poor performance in Windows 7 environment. You can have a look:
http://www.thinkdigit.com/forum/cpu...n-poor-performance-bulldozer-windows-7-a.html

Agree with you.In the End , its all about VFM.
Those who argue with this fact are either FanBoys or have enough money to spare for more powerful Intel build.

BTW, nice article there Cilus. Interesting read.
thanks for the explanation, if you already know that then why do you suggest that the fx 8350 is a processor of the future?

Processor of future , not sure but maybe because in future the OS will be able to utilize the Hardware more efficiently.
 

gagan_kumar

Wise Old Owl
it seems that from that thread because of software(os) only the cpu is lagging behind, otherwise amd has superior architecture .......

if i m not wrong the same case goes wid their GPU's also ..........
 
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NoasArcAngel

NoasArcAngel

Wise Old Owl
Agree with you.In the End , its all about VFM.
Those who argue with this fact are either FanBoys or have enough money to spare for more powerful Intel build.

BTW, nice article there Cilus. Interesting read.


Processor of future , not sure but maybe because in future the OS will be able to utilize the Hardware more efficiently.

lol bro, stop naming everyone a fanboy :p

Because performance per dollar ratio is far higher with FX-8350. For an end user, it does not matter whether it is a true 8 Core or not, for him, performance/Dollar ratio matters more. Last time, when I tried to explain, we got into some heated argument, leading to personal attacks. If you can keep your head cool, I can try to explain a little.

Also, I think you know that the poor performance of BD and PD are also attributed to the improper thread scheduling of Windows OS, it is not a hardware design fault all the time. In most of the Linux builds which have very good and optimized CPU thread management methods, both Bulldozer and PileDriver Flagship CPUs perform very closer to i7 2600K and i7 3770K, while offering far lesser price.

I am not at all any Fan Boy as you guys are thinking but I know a little bit of Computer Architecture and Game design. I have a good idea about how things work inside a CPU. If you can have a little patience then long back I have written article about BD design and its poor performance in Windows 7 environment. You can have a look:
http://www.thinkdigit.com/forum/cpu...n-poor-performance-bulldozer-windows-7-a.html

quite an interesting read, but the problem is that intel is dominating the market. So i see little reason why microsoft or any other software company for that matter would try and support amd in the future by giving better and cleaner optimized code for a specific cpu architecture? afterall everyone wants to jump on the bandwagon and have a piece of the pie. So its mainly this reason with which i argue that amd is not what the future is about. The bigger guy (intel) is creating a monopoly. There have been so many examples in the past, where the technology was top notch but it failed, and there is nothing you could do about that.
 
^ well, when one company starts dominating entire market, things like 'cheap processors will be locked' and 'if you want unlocked chips, say more, way more' happen. This is what Intel is doing because of their market dominance.
 
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