Integer clusters - What is it? (AMD CPU's)

[Enderegg]

http://en.wikipedia.org/wiki/List_of_AMD_FX_microprocessors

it says that the fx, are just half the core4s they have, but with the thereds they say they have core.
(something like that)

is it true then? they are kind of lying? (then most of i7 would be 8 core, and the extreme i7 would be 12 core)

 

[$hawn]

The thing is, AMD decided to club together 2 CPU cores, to make what is known as a module. Also, in order to reduce die size, they made some components as shared between the two cores. Each module still has 2 separate integer cores, but they now share the front end and the FPU.
Here's a BD/PD block diagram,

Coming to the FPU, it is actually comprised of two 128bit FPU's inside, but its still called as a single FPU, because they are fed by a single FPU scheduler. Also,if any core needs to execute a 256 bit FPU instruction, then these 2 128bit FPU's, can combine together and operate on the 256bit instruction. Very smart idea actually, given than 256bit FPU operations are encountered very rarely.

On the other hand, the sharing of the front end has the biggest impact on the per core performance of each core. AMD plans to address this issue in the Steamroller module, that will be released probably in a years time or less, by now offering a separate integer decoder for each core. Observe the difference here,

Intels hyperthreading meanwhile, is a similar, but follows quite a different approach. Each core can support 2 threads, but it is only one core in the end. If 2 threads are made to run on the hyperthreaded core, then they will share resources of the core, one at a time. This differs from AMD modules, wherein each integer core can be processing a different instruction simultaneously.

PS:- This topic has been a source of very heated arguments in the past If you ask me, AMD isn't lying, and each module is 2 cores. Technically speaking, the original 8086 'core' never even had a FPU in the first place!! Some people prefer to believe differently however.

 

[Enderegg]

Thank you! Very informative. Couldn't find this info anywhere! Thanks ( I'm liking more and more amd: on budget they are much better!)
Another thing : do you know when is steamroller coming out?

 

[$hawn]

Rumour's indicate that the APU version, called Kaveri should be out in Q3 of 2013, and the desktop AM3+ chips should be out by the start of 2014.
However, beware that AMD is known for delaying product launches

 

[Enderegg]

I'll probably buy fx6300 and then a fx8*** from excavator and another gpu for sli
Thanks once more