Why Does AMD bottleneck.

Jchinson

Commendable
Jan 19, 2017
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1,510
I have a 1060 3gb and an fx8320e. Works pretty good. My friend who has i5-4690k and gtx 970 is VERY close in performance, despite having a far less superior GPU. Why is this?
 
Solution
Although 8 cores @ 4ghz sounds good on paper, there's a lot more going on than just frequency and the number of cores.

cinebench-one.gif


We can see from this chart that on a core per core basis, an FX CPU is just about half as fast as a recent Intel CPU. Or, in other words, it takes 8 AMD cores to do the same work as 4 Intel cores. That would be alright if all software could fully utilize 8 cores, but many games and programs do not. Because of this, you end up with cases like this one, where a 2-core CPU @ 3.7ghz (Core i3 6100) performs the same as an 8-core CPU @ 4.7ghz:

r_proz_12.png



To make...
970 and 1060 are very close in performance so saying he has a less superior GPU is not true, and as Supahos points out you only have the 3gb card as well.

Now when you say the i5 and 8320 gets close in performance, what benchmark/test are you using?
Intel Haswell has a newer more superior archetecture then the FX serries (which is from 2012). So actual per core performance of the i5 is going to be noticably higher. Where the 8320 will still trump it at is in tasks that can utilize all 8 of its threads which is twice as much as na i5. Thus for video editing or games like BF1 that can utilize more then 4 threads the 8320 will show better performance, but for anything that can only use 4 threads/cores the i5 will win because it is more efficient.

 

Eximo

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Bottleneck is thrown around a lot, but it is not the end of the world. While an AMD CPU does tend to bottleneck recent high end GPUs, it is only a small percentage performance lost. Think like 10-20%, which would put you and your friend on a pretty even playing field.

When you already have parts and aren't considering upgrading everything, just get you can, don't go overboard with something like a Titan XP, but reasonable. Almost without exception there will be gains somewhere in the system by adding any faster part. (Except maybe large ram capacities, but then you could do things like SSD cache or RAM drives with it)

AMD chips tend to post similar maximum FPS with the same GPU. Where you see the difference is in the minimum and average. That is when the GPU has to wait on the CPU for data. That would apply to most GPU bound titles. CPU bound titles is another matter, games like GTA 5 show much lower numbers due to the lower IPC of AMD's architecture.

Hopefully that all changes when AMD releases their new line and we have some decent choices again.
 
Although 8 cores @ 4ghz sounds good on paper, there's a lot more going on than just frequency and the number of cores.

cinebench-one.gif


We can see from this chart that on a core per core basis, an FX CPU is just about half as fast as a recent Intel CPU. Or, in other words, it takes 8 AMD cores to do the same work as 4 Intel cores. That would be alright if all software could fully utilize 8 cores, but many games and programs do not. Because of this, you end up with cases like this one, where a 2-core CPU @ 3.7ghz (Core i3 6100) performs the same as an 8-core CPU @ 4.7ghz:

r_proz_12.png



To make matters worse, that 8 core CPU draws 4x as much power doing the same work.

EDIT: That's not to say FX CPUs are bad, but they're 5 years old at this point, and I wanted to illustrate that you can't just glance at cores and clocks and know how well a CPU will do.
 
Solution