Thruth about AMD CPUs (Inclusing gaming)?

[iplikator3333]

Hi,
So far I've seen so many people say different things about AMD CPUs, some saying that they completely suck and some saying that high end AMDs are almost as good as high end Intels, I don't know what to believe! And what about for gaming? I've also seen a lot of different statements about AMD vs Intel CPUs for gaming, Some saying things like "No one buying an AMD CPU cares even a little about gaming" and others like "It's not true what many people say that AMDs are bad for gaming, You can get a decent PC for gaming with an AMD CPU". I know that this will most likely start a fanboy war but I just want to know the truth!

 

[adamv1]

AMD CPU's Are less expensive than Intel. But you don't necessarily get what you pay for wit Intel. Intel chips are faster for most things, but just barely. For the extra hundred or so dollars you will spend on a i7 quad core, you could just get a solid state disk or 32 gigs of ram to make up the performance difference from an FX8320 8 core, or really quad core with hyper threading but AMD calls it 8 core.

Anyway toms already covered this in the Forum,

http://www.tomshardware.com/forum/353245-28-3770k-8350-help

 

[jaguarskx]

AMD CPUs and APUs have lower IPC capabilities than Intel CPUs. IPC is Instructions Per Cycle (or Clock). For every Hz Intel CPUs can process more instructions than AMD's APUs and CPUs. In a nutshell Intel CPU have architectures that are more efficient than what AMD has to offer. As an analogy it's like Person A can type 60 words per minute while Person B can type 70 WPM. Assuming no typing errors, guess who is going to finish typing a 5000 word document first.

Obviously both Intel and AMD offers multi-core CPUs. Intel offers up to 4 cores for the average person and up to 6 cores for enthusiasts who are willing to spend up to around $1,100 for a very powerful Sandy Bridge-E (socket 2011) CPU. AMD sells inexpensive multi-core CPUs for the "common person". The FX series has up to 8 cores which brings up the phrase "MOAR is better". But Intel has a trick up it's sleeve which has been around for quite a while. It's called Hyper Threading which basically creates 4 virtual cores; there are 6 virtual cores for the Sandy Bridge-E.

AMD's FX CPUs do have up to 8 physical cores unlike Intel's 4 physical cores + 4 virtual (or "fake") cores. However, while AMD's FX (Bulldoser and PileDriver) have more physical cores, every two core are paired up in a module. That module only has 1 FPU (floating point unit) that is shared by both cores. I one core is using the FPU, the other must wait. So while there are up 8 cores, the fact that they share an important resource diminishes the potential performance. The thought of having 8 cores is great, but only if they can be utilized. From a gaming perspective, the vast majority of games only use up to 2 cores. There are some that can make use of 3 or maybe 4 cores but they are few number. BF3 is an example of a game which I believe can use up to 6 cores (how effectively the game is using them is a different point), but only in multiplayer mode. In single player mode BF3 only use 2 cores. I believe ARMA 2 can use up to 6 or perhaps all 8 cores (I don't really know); but how effective the game is using them is a different story. Meaning is AMRA 2 only using 20% of the 5th core and 5% of the 6th core? I dunno.

In very basic layman's terms, Intel's Hyper Threading (HT) capable CPUs can process 8 threads of instructions much like an 8 core CPU, but half the threads must wait for the other threads for CPU and FPU resources. Imagine an 8 lane highway converging into a 4 lane highway. For a program to take advantage of HT, it must be designed to do so. The performance increase depends on how well HT has been implemented. It can be as low as a 10% increase in performance to as high as 50%. But games are not designed to use HT so buying a CPU like the Core i7-3770k for a pure gaming rig is more or less a waste of around $100 (the price difference between it and the i5-3570k), or something like that. I don't track prices.

So what hypothetically speaking, which design is better? 8 physical cores sharing 4 physical FPUs? Or 4 physical cores + 4 virtual (logical, "fake") cores sharing the resources of 4 physical cores? Obviously, 8 physical cores is potentially better than 4 physical and 4 virtual. However, what counts is how the various threads are prioritized to effectively provide the best theoretical performance. In some cases AMD's 8 cores wins, in other cases Intel's 4 cores + HT wins.


Sooo..... having said all that which CPU is generally better for games? Click the link below for some gaming benchmarks. It compares AMD's Piledriver FX-8150 8 core CPU @ 3.6GHz vs. Intel's Sandy Bridge Core i3-2100 dual core CPU @ 3.1GHz. It is a pretty lopsided comparison. Note I didn't choose the PileDriver FX-8350 and the Ivy Bridge Core i3-3220 CPUs because there were no game benchmarks. Scroll down towards the bottom.

http://www.anandtech.com/bench/Product/434?vs=677

As you can see, the Core i3-2100 performs better than the FX-8150. This go back to what I stated at the very beginning... IPC... Instructions Per Clock (or Cycle). Even though the Core i3 is clocked slower than the FX, the benchmarks indicates that the Core i3 performs better. That means for every 1Hz, the i3 can process more instructions compared to the FX.

The benchmarks also indicates (at least for those games), that having more core does not improvement performance. The 6 other cores are just there hanging out. It's like a group of 8 guys trying to get into a dance club to meet girls... the bouncer only lets two of them into the club and other 6 are just hanging out in the parking lot.

 

[jaguarskx]

By the way, the benchmarks in the link I provided above were ran with different resolutions. It would have been nice if a single common resolution was used because the higher the resolution, the more the important the GPU becomes when talking about game performance. Using low resolution solutions throughout all benchmarks would provide a better picture of the CPU's performance.

The results are actually a bit mixed in the benchmarks. But having said the above, if you play games at 1920x1080, then much of the performance difference between AMD and Intel will disappear for the most part. For example, that 23 FPS gap for Crysis Warhead will shrink. Too what? I don't know, but the performance difference will be less.

In Metro 2033 @1920x1080, the FX-8150 beats the Core i3-2100 by almost 2 FPS. Seriously... are you really going to notice the difference between 49.3FPs and 51FPS? In Dirt 3 @ 1920x1080, the Core i3-2100 beats the FX-8150 by about 3FPS. Again, seriously... Are you going to notice the difference between 99.3FPs and 102.3FPS? Also, if you have a typical 60Hz LCD monitor, your frame rates are going to be capped at 60FPS anyway. If you want higher FPS (assuming the CPU and GPU are capable of doing so), then you will need a 120Hz LCD monitor which caps FPS at 120.

 

[clutchc]

Since gaming is mainly about the graphics card(s), the difference between a fast Intel processor and a fast AMD processor won't be all that noticeable in the real world. As long as the CPU can keep up with the GPU, you won't notice the difference.

 

[sarinaide]

AMD's FX CPUs do have up to 8 physical cores unlike Intel's 4 physical cores + 4 virtual (or "fake") cores. However, while AMD's FX (Bulldoser and PileDriver) have more physical cores, every two core are paired up in a module. That module only has 1 FPU (floating point unit) that is shared by both cores. I one core is using the FPU, the other must wait. So while there are up 8 cores, the fact that they share an important resource diminishes the potential performance. The thought of having 8 cores is great, but only if they can be utilized. From a gaming perspective, the vast majority of games only use up to 2 cores. There are some that can make use of 3 or maybe 4 cores but they are few number. BF3 is an example of a game which I believe can use up to 6 cores (how effectively the game is using them is a different point), but only in multiplayer mode. In single player mode BF3 only use 2 cores. I believe ARMA 2 can use up to 6 or perhaps all 8 cores (I don't really know); but how effective the game is using them is a different story. Meaning is AMRA 2 only using 20% of the 5th core and 5% of the 6th core? I dunno.

I stipulated this in the AMD conjecture thread and have done enough tests to negat this argument. I isolated and ran each of the 8 cores on a FX 8XXX part independantly all capable of x86 instructions and single front end instructions execution. Enabling the paring core in the module doesnt virtualize the cores, they are two x86 processors duplicating the front end sharing the same pooled resources, this is not virtualization in what Intel has with HT. You cannot isolate a intel HyperThread independant of the 4 physical or 2 depending on the part because HT doesn't duplicate the front end. Hence why AMD CMT approach to SMT is around 1.85 of a dual core, that is down to the duplicated front end being over taxed on shared resources. Intels HT is around 1.1 of dual core so merely just a cheap low powered effort at SMT.

Your assertion of a FX8XXX being a Quad with virtualized cores is innacurate, non more so than AMD themselves explaining the function of the module. while a module is not a native x86 core with its own resources such as in K10, the sharing of a resource pool doesn't make it virtual, think you misunderstand the nature of AMD CMT design.

 

[satyamdubey]

I stipulated this in the AMD conjecture thread and have done enough tests to negat this argument. I isolated and ran each of the 8 cores on a FX 8XXX part independantly all capable of x86 instructions and single front end instructions execution. Enabling the paring core in the module doesnt virtualize the cores, they are two x86 processors duplicating the front end sharing the same pooled resources, this is not virtualization in what Intel has with HT. You cannot isolate a intel HyperThread independant of the 4 physical or 2 depending on the part because HT doesn't duplicate the front end. Hence why AMD CMT approach to SMT is around 1.85 of a dual core, that is down to the duplicated front end being over taxed on shared resources. Intels HT is around 1.1 of dual core so merely just a cheap low powered effort at SMT.

Your assertion of a FX8XXX being a Quad with virtualized cores is innacurate, non more so than AMD themselves explaining the function of the module. while a module is not a native x86 core with its own resources such as in K10, the sharing of a resource pool doesn't make it virtual, think you misunderstand the nature of AMD CMT design.

I am so glad that you posted this. On the few occasions that I have explained someone smt, I have mostly put AMD's solution as, a module being = 1.75 of a pure core and HTT= 0.2 of an Intel core. Now I know that the difference is even bigger.

 

[sarinaide]

Another way to test this is, take any AMD FX processor, go to bios you will see cores listed #1-8 (depending on the FX part) you can disable all but one, go to windows use CPUID and it will list as 1 core 1 Thread, enable the second core in the module and you get 2 cores 2 threads, if it was virtualized it would be 1 core, 2 threads, 2 cores, 4 threads.

FACT: FX use 4, 6 and 8 cores just not native cores as they share resources and duplicate the front end when both cores in the module are loaded up.

When AMD sorts out the front end, ie: SteamRoller the 20% penalty will deminsh some way, not only will IPC improve but CMT/SMT will also dramatically improve. It is why a good majority of AMD fans that have been here from the start have said that modulation is somewhat ahead of its time, but AMD needed to gamble and on HSA, playing intel at x86 would have sunk them a long time ago. Right now AMD have modular arches and HSA, both are still in the infancy stage but from Zambezi to Vishera are definitely improving.

 

[spartansociety]

To keep it simple


Intel plus's
i5's and i7's are MUCH faster than any AMD CPU you can buy
more power efficient
run cooler

Amd plus's
lower end CPU's can be good for cost
dont need to upgrade motherboard as often when upgrading cpu
fastest cpu's have a better integrated GPU

If you buy an i5 or i7 your cpu WILL be much better than any amd cpu.

My gaming PC has an overclocked intel 2500k
My little netbook that doubles as a temporary media pc has a AMD E-450

 

[BuddiLuva]

There's nothing wrong with AMD CPUs, they can be just as good and better in some scenarios, against Intel CPUs in their price range.

People need to stop looking for an excuses to justify the extra money they spent on a CPU that performs similarly to avoid regret.

BECAUSE
It all falls down to GPU, and I don't give a *** If you're running an i7 3990x. If you've blown your money on that and can't afford a decent GPU. I've got news for you, that shitty little 4100 FX with a 7850 is gonna destroy you.

My point being, do not worry about which is better, because the performance difference is marginal. Look at pricing, pick the cheaper CPU and put that saved money into getting a better GPU.

You can't lose that way.

 

[spartansociety]

There's nothing wrong with AMD CPUs, they can be just as good and better in some scenarios, against Intel CPUs in their price range.

People need to stop looking for an excuses to justify the extra money they spent on a CPU that performs similarly to avoid regret.

BECAUSE
It all falls down to GPU, and I don't give a *** If you're running an i7 3990x. If you've blown your money on that and can't afford a decent GPU. I've got news for you, that shitty little 4100 FX with a 7850 is gonna destroy you.

My point being, do not worry about which is better, because the performance difference is marginal. Look at pricing, pick the cheaper CPU and put that saved money into getting a better GPU.

You can't lose that way.

Except that all games are not GPU bound. I play alot of strategy games in which cpu's are much more important. In Starcraft 2 my 2500k at 4.3 ghz struggles to stay above 30 frames per second let alone the ideal 60. FX cpu's hit low teens according to this benchmark http://www.tomshardware.com/reviews/gaming-fx-pentium-apu-benchmark,3120-6.html .
Other games i play that need a cpu more than video card include Civilization 5 and Europa Universalis 3. None of this even takes account of the fact that I have a multi monitor setup where i use other programs at the same time. If you don't use your computer in a way that needs alot of CPU power that's fine, but don't judge others as wasteful because you assume everyone uses their computer in the same way. With a 6950, SSD and 8gb ram, the only bottleneck i have ever had reduce my enjoyment from a game has been caused by the CPU.

 

[BuddiLuva]

Except that all games are not GPU bound. I play alot of strategy games in which cpu's are much more important. In Starcraft 2 my 2500k at 4.3 ghz struggles to stay above 30 frames per second let alone the ideal 60. FX cpu's hit low teens according to this benchmark http://www.tomshardware.com/reviews/gaming-fx-pentium-apu-benchmark,3120-6.html .
Other games i play that need a cpu more than video card include Civilization 5 and Europa Universalis 3. None of this even takes account of the fact that I have a multi monitor setup where i use other programs at the same time. If you don't use your computer in a way that needs alot of CPU power that's fine, but don't judge others as wasteful because you assume everyone uses their computer in the same way. With a 6950, SSD and 8gb ram, the only bottleneck i have ever had reduce my enjoyment from a game has been caused by the CPU.

What you have to take in mind is that people do not crap money, otherwise YAY lets all pull out i7s with HD7990s. But no, it does not work that way, you are going to suffer from either one side of the fence or the other, that's the way it is. Now what I've advised is best to balance it out, now if you knowingly when an bought an 2500k and a 6990 knowing that your main interest would be in games that require massive CPU rather than GPU, then that is your problem. Maybe if you had cut back with the GPU you would have been able to purchase a slightly better CPU.

Or you're gonna have to save up.

Not to mention that the benchmark you have just shown is the Bulldozer series but I'll look passed that.

 

[BuddiLuva]

Apologies, I meant 6950. TH doesn't let me edit posts.

 

[spartansociety]

What you have to take in mind is that people do not crap money, otherwise YAY lets all pull out i7s with HD7990s. But no, it does not work that way, you are going to suffer from either one side of the fence or the other, that's the way it is. Now what I've advised is best to balance it out, now if you knowingly when an bought an 2500k and a 6990 knowing that your main interest would be in games that require massive CPU rather than GPU, then that is your problem. Maybe if you had cut back with the GPU you would have been able to purchase a slightly better CPU.

Or you're gonna have to save up.

Not to mention that the benchmark you have just shown is the Bulldozer series but I'll look passed that.

My CPU purchase is not the issue. I bought a 2500k - partially because it was recommended on this websites CPU guide as the best gaming CPU you could buy without spending 1000's. Overclocked, its still much faster than any Ivy bridge i can buy for what I use it for (and is a little easier to overclock). If i could improve these games with a new CPU I would. The poster says that he has heard that "high end AMDs are almost as good as high end Intels" this to me is crap. I think we would both agree that if your budget for a CPU makes it to a couple of hundred dollars then Intel has much better options than AMD and Intels high end cpu's destroy anything AMD can come up with. If your spending less than 200 i would agree that AMD cpu's can be a good choice. For my new media pc i am considering an AMD APU but the extra heat and electricity is a big minus compared to Intel i3's.

As to your argument about spending more on gpu's, I think of it this way. With a 6950 i can always turn settings down a little and still get the frame rate i want, but this is not something that is always possible in CPU bound games.

 

[sarinaide]

Well AMD don't have a FX SKU over $200 so the point of "if you are building under $200" is rather moot.

 

[spartansociety]

true, although i would still argue that the main advantage AMD has is their APU's and that FX cant really compete with intel ATM....or the way they seem to be going with their finances and staffing, maybe ever.

 

[Brynadinaling]

Depends how much you have to spend, the question is AMD 4 core FX 4100 or 2 core intel i3 which both go for the same price. surprisingly in bench mark tests overall the i3 is still better due to the FX chips using of slowing down when not really being used. gaming are mostly better on intel, its a farcry from the old days

 

[BuddiLuva]

My CPU purchase is not the issue. I bought a 2500k - partially because it was recommended on this websites CPU guide as the best gaming CPU you could buy without spending 1000's. Overclocked, its still much faster than any Ivy bridge i can buy for what I use it for (and is a little easier to overclock). If i could improve these games with a new CPU I would. The poster says that he has heard that "high end AMDs are almost as good as high end Intels" this to me is crap. I think we would both agree that if your budget for a CPU makes it to a couple of hundred dollars then Intel has much better options than AMD and Intels high end cpu's destroy anything AMD can come up with. If your spending less than 200 i would agree that AMD cpu's can be a good choice. For my new media pc i am considering an AMD APU but the extra heat and electricity is a big minus compared to Intel i3's.

As to your argument about spending more on gpu's, I think of it this way. With a 6950 i can always turn settings down a little and still get the frame rate i want, but this is not something that is always possible in CPU bound games.

Now that I can understand, and I will agree that highest end Intel will demolish highest end AMD without even a shadow, but there's a factor that comes in between those unreasonable comparisons: Price, now if you even have to compare a £150 to a £300+ CPU then there's something wrong there, because that £150 shouldn't even touch the £300 one and it isn't meant to.

However if we look at £150 CPUs on both sides, we can say that the performance difference from Intel to AMD is marginal as I said previously on my posts.

(For people living in US: £150 is about $200 (I think))

 

[satyamdubey]

i3 is still better due to the FX chips using of slowing down when not really being used.

I could not understand that. cpu's slow down when not being used both Intel and AMD do that. Thats speed step and cool&quiet technologies.

 

[sarinaide]

true, although i would still argue that the main advantage AMD has is their APU's and that FX cant really compete with intel ATM....or the way they seem to be going with their finances and staffing, maybe ever.

Well I think from what I have tested and what the general concensus is that AMD FX is still good enough even for a gaming build in the $1000 window, it comes down to how much you need over and above what is good enough. In many scenarios the AMD parts don't fall far behind Intels line and the mere 2-3 FPS is made up easily on a jump from DDR3 1866 to DDR3 2133 or with a better graphics card.

As I did above there are issues still being ironed out in AMD's arch, but even in the worst case is still copious. Still a very attractive alternative at the price point

 

[BuddiLuva]

Plus we shouldn't even be using the 4100 as a comparison, it's irrelevant.

 

[spartansociety]

Now that I can understand, and I will agree that highest end Intel will demolish highest end AMD without even a shadow, but there's a factor that comes in between those unreasonable comparisons: Price, now if you even have to compare a £150 to a £300+ CPU then there's something wrong there, because that £150 shouldn't even touch the £300 one and it isn't meant to.

However if we look at £150 CPUs on both sides, we can say that the performance difference from Intel to AMD is marginal as I said previously on my posts.

(For people living in US: £150 is about $200 (I think))

true, but my point is there are alot of people for who the extra hundred or so on the CPU is well worth it, in these cases Intel is indisputably better. If your not one of these people, then you need to do some research in your price range and decide what works for you.

 

[satyamdubey]

I would like to add that let us not forget the fact that AMD would have definitely priced their cpu's more aggressively if they were as good in performance as Intels.

There is a reason why AMD is willing to offer cpu's under $200.

 

[jaguarskx]

AMD's FX CPUs do have up to 8 physical cores unlike Intel's 4 physical cores + 4 virtual (or "fake") cores. However, while AMD's FX (Bulldoser and PileDriver) have more physical cores, every two core are paired up in a module. That module only has 1 FPU (floating point unit) that is shared by both cores. I one core is using the FPU, the other must wait. So while there are up 8 cores, the fact that they share an important resource diminishes the potential performance.

Your assertion of a FX8XXX being a Quad with virtualized cores is innacurate, non more so than AMD themselves explaining the function of the module. while a module is not a native x86 core with its own resources such as in K10, the sharing of a resource pool doesn't make it virtual, think you misunderstand the nature of AMD CMT design.

You quoted my post, yet you seem to have failed to comprehend what I have stated.

I have bolded my original statement where I have declared that AMD's FX CPUs do in fact have 8 physical cores; in red bolded text.

In the blue bolded text, I stated it is Intel's CPUs which have 4 physical cores and 4 virtual cores.

 

[gamerk316]

I have bolded my original statement where I have declared that AMD's FX CPUs do in fact have 8 physical cores; in red bolded text.

Technical talk time!

Technically, the second core of a BD module isn't a full "core" in a traditional sense, because as like Intel HTT, it has to share resources with another core. In BD's case, the front end scheduler and FP units are shared between cores on a BD module, so you get about 75% of the performance when the second core of a BD module is used.

By contrast, Intel HTT is a much more barebones implementation to SMT; only the registers are duplicated and most every other resource is shared, so there is a very minimal performance gain to HTT (barring Register to Register instructions, which are uncommon for most workloads).

So I consider "8 cores" a stretch, because when using all "8 cores", you have 4 cores that get ~75% performance compared to the others, so you have performance closer to a true 6-core CPU (*cough1100Tcough*).

The fact MSFT put out a Windows patch to treat BD modules the same way as Intels HTT cores should have put an end to this argument. As far as the windows scheduler (post patch) is concerned, the second BD core of a module is not preferred due to its latent performance hit.