AMD APU´s A-series

Rui Neves · Jan 13, 2015

There´s any APU of A-series (AMD) with 4 physical cores ?

mdocod · Jan 13, 2015

Depends on what side of the grey line you're standing on.

The Kaveri A8 and A10 series are sold as 4 core and have very good MP scaling characteristics (up to ~+95%) but still have some shared resources (2 module design).

spdragoo · Jan 13, 2015

Both the A8 and A10 series are quad-cores.

Vipinven2015 · Jan 13, 2015

Suggest you have a check on the latest A8-7600K

Rui Neves · Jan 13, 2015

mdocod :

I have an amd a8 6600k but seems that 2 cores are logical

Rui Neves · Jan 13, 2015

spdragoo :

I have an amd a8 6600k but seems that 2 cores are logical

Rui Neves · Jan 13, 2015

mdocod :

so my cpu (a8 6600k is 4 core physical ) ?

Rui Neves · Jan 13, 2015

Vipinven2015 :

thanks looks nice , it´s a thing to think to upgrade for.

mdocod · Jan 13, 2015

Uh... if you already have an A8-6600K there's no point in upgrading to Kaveri UNLESS you intend to use software which leverages HSA optimized branches of code for improved performance. I'm not aware of any mainstream software being developed and compiled to take advantage of HSA at this time.

You already have a "dual module/quad core" CPU, the A8-7600 is also a dual module quad core CPU. Kaveri is more refined, but not enough to makeup for the clock speed loss you would suffer going to the 65W 7600.

Due to the way that resources are shared in PileDriver architecture CPUs like your's, the Operating system task scheduler is configured to treat the second core of the same module as a "logical" core instead of a "physical" one for performance reasons. These are superficial distinctions used at the software level to ensure that multiple threads are assigned to separate modules whenever possible.

In the case of Intel Hyperthreading, the same scheduling technique is used, but the superficial distinction of "logical" vs "physical" is actually much more accurate, even though a haswell core has more execution resources than a piledriver module, those execution resources are still arranged into a single very wide execution engine. In A pileDriver module, there are indeed 2 distinct sets of equal execution engines that are effectively isolated (a single thread can not have work assigned on both of these execution engines simultaneously, it's physically impossible). The module does however, share a large front-end, instruction decoder, and FPU instruction engine across both cores. This is where the "grey line" problem comes in. For workloads that bottleneck on instruction decoders or the FPU piplines, it's more like a single core.

Rui Neves · Jan 13, 2015

mdocod :

Uh... if you already have an A8-6600K there's no point in upgrading to Kaveri UNLESS you intend to use software which leverages HSA optimized branches of code for improved performance. I'm not aware of any mainstream software being developed and compiled to take advantage of HSA at this time.

You already have a "dual module/quad core" CPU, the A8-7600 is also a dual module quad core CPU. Kaveri is more refined, but not enough to makeup for the clock speed loss you would suffer going to the 65W 7600.

Due to the way that resources are shared in PileDriver architecture CPUs like your's, the Operating system task scheduler is configured to treat the second core of the same module as a "logical" core instead of a "physical" one for performance reasons. These are superficial distinctions used at the software level to ensure that multiple threads are assigned to separate modules whenever possible.

In the case of Intel Hyperthreading, the same scheduling technique is used, but the superficial distinction of "logical" vs "physical" is actually much more accurate, even though a haswell core has more execution resources than a piledriver module, those execution resources are still arranged into a single very wide execution engine. In A pileDriver module, there are indeed 2 distinct sets of equal execution engines that are effectively isolated (a single thread can not have work assigned on both of these execution engines simultaneously, it's physically impossible). The module does however, share a large front-end, instruction decoder, and FPU instruction engine across both cores. This is where the "grey line" problem comes in. For workloads that bottleneck on instruction decoders or the FPU piplines, it's more like a single core.

Thanks for your explanation mate , very good explanation and can help other people like me. now You can explain me why do I have some strange fps drop on fifa 15 only on replays , corners , free kicks and when my player is close to the corner flag ? (I run the game always at 60 fps exept on these parts).

My config is :
RAM 4gb 1666mhz
ASUS r7 250x 1gb ddr 5
amd a8 6600k

I will be very apreciated if you can help me

mdocod · Jan 13, 2015

I would start by making sure you have disabled the iGPU on the APU in BIOS, as this should help ensure that you have full access to your system memory. Upgrading to 8GB of memory may help. It's also very likely that the software itself is causing the glitches (bugs, effectively), especially if they always happen in the same specific conditions. Do a Google search and you will probably find lots of other users with "glitchy" performance in this game.

What motherboard do you have?

Rui Neves · Jan 13, 2015

mdocod :

I have a msi a88xm e-35

Rui Neves · Jan 13, 2015

mdocod :

How do I disable igpu ?

mdocod · Jan 13, 2015

Unfortunately, the E35 and most other MSI made FM2/+ boards are missing LOTs of important controls in BIOS... Including the ability to enable and disable the iGPU or adjust the amount of RAM dedicated to the iGPU, as well as voltage controls for the CPU, CPU-NB etc.

Rui Neves · Jan 14, 2015

mdocod :

that´s bad

, there´s is other way to disabe igpu besides on bios ?
I can´t find anything good on internet about my issue , i tried somethings but without sucsess , i tried to unlock 60 fps that I have locked for and i have between 70 and 75 fps but have the same issue

mdocod · Jan 14, 2015

More memory, if that doesn't fix it, it's probably software related and there's nothing you can do.

Rui Neves · Jan 14, 2015

mdocod :

Ok thanks for all

AMD APU´s A-series

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