Solid answer/explanation about AMD FX-4300 core count

[mrmoosemanlickme]

When I purchased this CPU, I was informed that it was a 4 core, 4 thread CPU. Some software that I have supports this, some that I have says its a 2 core, 4 thread. Yes, I have it overclocked to 4.2, but I don't think that should affect how physical/logical processors show up. If there is a reason as to why some programs show the core count differently an explanation would be nice.

There's another post similar to this one but it doesn't quite go into much depth, but it explains that the FX-4300 is made of 2 2 core modules that would be read sometimes as four cores. Could this be similar to newer AMD cpus being made up of multiple 4 core "chiplets" to make a total of 16 or so cores in newer CPUs?

Link to screenshot gallery

Thanks for any responses!

 

[Eximo]

Sort of. The FX chips are a little odd in that they truly do have the core count. However, they share resources between the chips.

https://en.wikipedia.org/wiki/Bulldozer_(microarchitecture)#/media/File:AMD_Bulldozer_block_diagram_(8_core_CPU).PNG

I couldn't find a similar diagram for Piledriver, but they aren't all that different. Plenty of logical diagrams, but they aren't as clear in showing what each CPU module contains.

Cut that in half and you have your CPU. The big thing there is the shared FPU.

So the easiest thing for your CPU to do is run one core on each module. When you want to use the 3rd or 4th core it takes extra clock cycles to switch the data to the other core, than to receive the computation back.

So some use cases weren't perfect for the FX chips, but they were a cheap way to get a high core count. Just that some workloads didn't work as well as say straight up cores or even Intel's HT.

AMD's architecture with Ryzen now more closely matches what Intel has had for a long while. The chiplets are fully functional CPUs on their own but communicate across an interposer.

 

[geofelt]

It really is a moot point.
Windows dispatches threads.

Sometimes threads share resources like in the FX line or with intel hyperthreading.
When a thread shares resources, it will sometimes be a bit slower if it needs to compete for resources.
By and large, you can use the passmark ratings to get an idea of comparisons.

 

[Eximo]

I suppose that is sort of true. Really comes down to what the CPU can actually do.

My understanding with FX chips was that it is inherently a less efficient design than the Phenom chips that came before it. So they had products released that competed with themselves and didn't do much to match what Intel had already released, let alone what they released over the next several years. Piledriver was a little better and by then Windows had solved some of the problems they had at the architecture's debut.

Regardless, if you bought this recently you were somewhat deceived. As there are plenty of dual cores and cheap quad cores that are faster. Most i3s and later Pentiums, and even some of the Athlon chips were competitive with the low end FX chips. At a time when high core count didn't matter all that much for gamers it didn't make a big splash.

Sadly it matters more now, but the chips are just too dated to compete with the lower core count chips of today.