Fx range and intel for sli-ing

[madcap42]

Ok, i am getting lots of contradictions on whether the AMD fx 8350 will bottleneck in sli with two gigabyte gtx 670 cards yet the only people who say it will are intel user's lol, What is the truth of the matter since amd's fx 8350 piledriver is a newish chip 8 core why would it bottleneck does not make sense and if so why would amd release that processor without addressing the issue of sli

 

[Scott_D_Bowen]

It doesn't have 8 cores, it has 4 cores and AMDs version of HyperThreading.
- Sadly AMD suck at managing resource contention within their SMT solution.

Here, we can see it bottlenecking 12.5% of frames, that is 1 in 8 frames.
- http://techreport.com/r.x/amd-fx-8350/crysis-latency.gif
- That is one f**cker of a curve ball for an 'eight' (cough, four SMT) core AMD processor!

The 8150 is even worse:
- It chokes 25% of all frames rendered!

FYI, that wasn't even using SLI or CrossfireX, it was just using one of AMDs own GPUs:
- XFX Radeon HD 7950 Double Dissipation 3GB with Catalyst 12.3 drivers

PS: I used to love the Athlon 64 X2's, etc, but these new AMD chips are absolute rubbish.

 

[manofchalk]

AMD chips and boards can SLI without issue. Just make sure you have the basic compatibility (dual 8x slots on the board, enough power and a strong enough processor to not bottleneck) and your fine.

Also the 8350 being a true 8-core is up for debate. Bulldozer modules (Which is essentially what the Piledriver chips use) don't exactly fit the traditional definition of a "core".

Anyway, I don't see any issue with an 8350 bottle-necking dual 670's.

 

[Scott_D_Bowen]

AMD don't make a strong enough processor not to bottleneck a modern SLI solution.
- That's the problem.

 

[weaselman]

You may have and 8 core cpu, but you have to remember sometimes it comes down to how some games are made, for example we have had four core cpu`s for quiet a time but some games still don`t make full use of all the cpu cores in a said game.
I dont know if anyone has told you or you know but if you think the cpu could be the cause you could always reduce some of the load as you have an SLi setup.
One solution would to be set the physics in the game to use one ofthe 670 cards and the other if you can to deal with the graphics processing. The options to change the settings will be in the Nvidia control panel. This would take a bit of load off the cpu, letting it deal with other things.

 

[madcap42]

AMD chips and boards can SLI without issue. Just make sure you have the basic compatibility (dual 8x slots on the board, enough power and a strong enough processor to not bottleneck) and your fine.

Also the 8350 being a true 8-core is up for debate. Bulldozer modules (Which is essentially what the Piledriver chips use) don't exactly fit the traditional definition of a "core".

Anyway, I don't see any issue with an 8350 bottle-necking dual 670's.

That's what i thought since the cache are bigger than it's predessor's fx 8150 and has piledriver

 

[manofchalk]

It doesn't have 8 cores, it has 4 cores and AMDs version of HyperThreading.
- Sadly AMD suck at managing resource contention within their SMT solution.

AMD doesnt have any version of Hyperthreading, nor any similar tcehnology. They way they achieve the "8" cores is by using Bulldozer Modules, which in a nutshell is two processing units with a single memory cache (a traditional core is a single processing unit and cache). This is why they have great multi-threaded performance and weak single threaded, its the way the architecture is set up.
If they had Hyperthreading like technology and traditional cores then it would be roughly similar to the Intel lineup for performance.

 

[madcap42]

You may have and 8 core cpu, but you have to remember sometimes it comes down to how some games are made, for example we have had four core cpu`s for quiet a time but some games still don`t make full use of all the cpu cores in a said game.
I dont know if anyone has told you or you know but if you think the cpu could be the cause you could always reduce some of the load as you have an SLi setup.
One solution would to be set the physics in the game to use one ofthe 670 cards and the other if you can to deal with the graphics processing. The options to change the settings will be in the Nvidia control panel.

Yes i agree on that

 

[Scott_D_Bowen]

It's not how the games are made, it's how the CPU is made.
- It's not a real 8 core CPU, just like the Core i7 isn't a real 8 core CPU.
- The OS just 'sees' 8 cores.
- In fact it's even worse than HyperThreading, as they share more resources and dedicate less to cut costs!
- This is AMDs version of SMT, which isn't that different from Intel's current implementation of HyperThreading on the current Core i7.

Those 'cores' are in pairs, and each pair shares resources.
- Most games just expect a 'normal-ish' x86 + SSE CPU
- Nothing unreasonable about that, eh?
- When they see 8 cores and try to use them you get resource contention, which causes heaps of stuttering (not micro-stuttering).
- Even Intel's HyperThreading didn't kill performance this badly when it debuted.
... back in those days the ~AthlonXP1700+ really had the edge.


Software Developers don't like spending 6.2 million extra hours 'tuning' their post compiled code just for one dodgy CPU
- Think about it!
- Did we get anything from Intel SMT (HyperThreading) besides better video encoding?
- It's bloody expensive.

This is the wondrous FX-8350 of which you speak, with all it's cache and glory, in a well optimized title:

- Image how that curve looks in a title that isn't tuned?


Why anyone would build a SLI rig (dedicated resources to 3D) around a CPU that shares so many resources between cores makes so little sense at all.
- Just look around the 16.6667ms mark in the graph above, that intersecting point is the percentage of frames that are under 60fps.
- Why run at 128fps to 256fps average, if 15% of your frames will be bottlenecked by the CPU?

 

[manofchalk]

^ Are you implying I'm defending the 8350? I fully realize it performs worse than its equivalent Intel (3570k) in gaming situations.

I was just stating that it doesn't have any version of Hyperthreading, that its 8 threads is because of an actual hardware solution, rather than a software (not sure on right word) like Hyperthreading.
Just explaining the core comments that popped up.

 

[Scott_D_Bowen]

SMT is SMT, it doesn't matter how AMD brand it.
- They understand their fan base, and know how to exploit them.
- They're a company first, so they have shareholders and profits to worry about legally as their first priority.
- Actually making a good product comes 2nd place (if that).


If you don't think it's SMT, then prove to me that it isn't with just three URLs.
- AMD have already advised that disabling 'every 2nd core' improves performance.
- If it wasn't SMT then they'd just say 'disable half the cores' and not specify which ones to disable.

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

I'll admit AMD are fantastic at branding their tech as 'something more than it is' while 'using even less transistors to implement it, so it only works on paper and in the server room'.

 

[manofchalk]

Will admit I only have a basic understanding of Threads and the more intricate workings of a CPU. But from what I do know, in a non Hyper-Threaded (or similar technology) CPU, one core = one thread. That's why an i5 has 4 threads and an i7 has 8 despite both being Quad Cores, the Hyper-threading makes each core support another thread.

Bulldozer modules are essentially dual cores (if you relax the definition of a "core"), and there are four of them in the 8350, so 8 threads are made.

All I'm saying is that the 8350 has 8 threads due to hardware, rather than a more software-ish solution like Hyperthreading.

 

[Matthew Collette]

Proud owner of amd FX 8350 with SLI GTX 770 . Absolutely amazing. I'm sure Intel has better everything but I've got more money in my bank and enjoy gaming with out any interruptions.