As topic.
 
Please do not ask me to get a new cpu.. i just bought the Fx8350 (clocked to 4.2ghz with hyper evo 212. cant go further than 4.2ghz) together with its mobo weeks ago.. Appreciate the help

This will answer the question about bottle necking, pretty much unless your using an i3 and maybe in some rare circumstances an i5.   I can't post links yet as I've been a silent observer on this site for the last year but here you go www (dot) youtube (dot) com/watch?v=DAgpvWc94VBM .  Basically your not going to bottle neck your GPUs as long as you use the right class of processor for gaming.  Anyway watch the video you'll learn a lot about this.  

The one thing that he doesn't cover, that *might* be a problem at the 3 and 4 card level, although I don't think there is a GPU/CPU combo that utilizes a full PCIe x16 or x8's worth of bandwidth is that your processor only has a few channels it can communicate with the GPUs on.  You are reducing the amount of data each card can receive, this is why they put a marker like this on the motherboard specifications 2 (single at x16 or dual at x8/x8 mode).   It's actually not a limitation of the MOBO in most cases but the processor.    This post led me down curiosity lane, so I found an answer to it, it would appear that this shouldn't bottleneck a GPU or Processor to any noticeable extent.  In fact the gain you have from running in 3 way SLI would negate the loss and then some.  Here is the article www (dot) tested (dot) com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/
 
While I know there are some people who swear up and down that you can bottleneck your GPU  if you don't have an Intel Haswell-E X class processor and mobo that simply isn't true, as long as your midrange i5 and up you should be okay, and of course the AMD equivalents should be fine too.  I tend to speak in Intel terms because of the problems I had with AMD parts between '99 and '04 when building home computers.  They led me to swear off AMD anything for a long time, and just as I was about to come around my friend started having problems with his AMD GPU and I renewed my swearing off of their stuff.  Anyway i really do hope this helps, and feel free to hit me up with any follow on questions.
 
Cheers MARPAT
 
Copy and paste FTW

There is no simple 'yes' or 'no' because we all have different system configurations and play different games.  This is going to require a lot of thinking on your part.

1. What graphics cards are you coming from?
2. What is your monitor resolution and do you plan on upgrading?
3. What games do you play or plan to?
4. Does you mainboard support SLI to begin with (does it say SLI support on the box/manual or on the board itself anywhere)?

To answer your question: It depends on your games.  If you largely play CPU-bound titles like anything in multi-player or simulator or RTS/RPG, then yes your CPU could hold your graphics cards back.  But if you play GPU-bounded, then the CPU type and clockspeed don't matter so much because the load is going on the GPUs.  NOTE: It isn't that the CPU does less work in a GPU-bound title versus a CPU-bound title, the CPU's share of work is somewhat the same while the GPU's share is more on a GPU-bound titles, that's all.  If you're going to SLI/CFX, it would make more sense to play those types of games; don't just assume any game you have will improve with additional cards.  You need to find out support before hand by Googling your game with the keywords "SLI support" and do some research.
 
I've noticed in CPU reviews, an AMD system will not have that much of a loss of frame rates at higher resolutions, while an Intel system will clearly drop, for instance, this guru3D reivew of FX8350.  This implies that a game is GPU-bound when on an AMD system and CPU-bound when used in an Intel system.  But only because the AMD system typically has much lower frames rates than an Intel system with the same graphics cards = people claim CPU bottleneck.  It isn't always true; you just have to pay attention to what sets everything apart: Game type.
 
Look back at the guru3D review.  The game Far Cry 2 shows a massive difference between AMD and Intel-- only if you play at low resolutions.  But at higher resolutions, the gap is smaller and couldn't possibly justify the costs to make the swap unless you had your heart set on the best.  Looking at Crysis 2, that game is nearly 100% GPU-bound at 1920x1200 resolution where every single processor type results in the 50's fps.  Only way to increase frame rates is with another graphics card.
 
In that sense, we can't say if your CPU could bottleneck as long as you invoke GPU-bound scenarios; for anyone among us to say otherwise are just morons.  Unfortunately, there are a lot of cheerleaders on this website that think they are doing the companies they purchase from a favor by slamming others.  I don't get it, but I hope you can weed through them and not get discouraged.

 
I just wish you had asked us before buying the CPU. The 4790k would have been the better choice.         

Rendezvous

XrayMan
 
I just wish you had asked us before buying the CPU. The 4790k would have been the better choice.         

What type of motherboard do you have? If your coming from an amd cpu to a Intel Cpu you would have to get tha an lga 1150 socket not am3+. Also you might as well stick with amd and get AMD Fx 9370 or 9590..you can keep your mobo, they are on par with intel i7's , they are cheaper, and they run faster right out of box with no OC.

Eh, not really man, i guess it depends what you are using it for and what you mean by ''on par'' because from everything i've seen, they aren't on par, like at all.
But, i don't have FIRST hand experience, just from research, i was looking at them pretty hard on the last build i did for someone.

As I posted before, unless your not running a "gaming" grade CPU your not going to experience bottle necking.  For all intents and purposes it is a phobia of gamers, especially ones that are in the market for an _80+ card.  It really just doesn't happen on gaming CPU/MOBO/GPU combos.  It's irrational to have all these threads, honestly if you want to know what is going to "bottleneck" your system?  It's the SATA connections in your computer, when is the last time you actually saw 6Gb/s on a SATA?  Never, because the hardware at the other end of the cable can't handle those speeds.  Personally that is why I got my self 32GB of RAM for some of the more intensive games, so I can load them onto a ramdisk and run them when I need them to perform.  Even then I don't get the speeds i'm supposed to get on the RAMdisk.  Probably because Windows "bottlenecks" the system, which is why I use Linux for work, and windows is mainly for gaming.
 
I am sorry this is starting to look like a rant so I'm gonna kill it.  The moral of the story, unless your on a CPU that just can't handle gaming anyway you should be alright.  Once again I post this video watch it love it and enjoy:
www (dot) youtube (dot) com/watch?v=DAgpvWc94VBM 
 
cheers,
Marpat
 
 

trek554
some of you just dont have a clue. there are games where an 8350 cant even come close to matching a 4790k with even a single gpu. and again there are some games where an 8350 cant even stay above 60 fps. heck in Thief it cant even average 60 fps. 
 
SLI 980 on an 8350 is just a silly waste of money unless using a super high resolution. 

Yeah but that is more of a processor issue than a "bottleneck"  I am sure that the GPU is running at 100% in both cases.  I've said it before and I'm sure in my job I will say it a million more times before I retire, I have a history of problems with AMD processors and GPUs, it's not that I'm a fanboy perse.  I've just never had luck with AMD products.  There is a reason that Intel gave them access to their patents so they wouldn't go under and die.

trek554

MARPATdroid

trek554
some of you just dont have a clue. there are games where an 8350 cant even come close to matching a 4790k with even a single gpu. and again there are some games where an 8350 cant even stay above 60 fps. heck in Thief it cant even average 60 fps. 
 
SLI 980 on an 8350 is just a silly waste of money unless using a super high resolution. 

Yeah but that is more of a processor issue than a "bottleneck"  I am sure that the GPU is running at 100% in both cases.  I've said it before and I'm sure in my job I will say it a million more times before I retire, I have a history of problems with AMD processors and GPUs, it's not that I'm a fanboy perse.  I've just never had luck with AMD products.  There is a reason that Intel gave them access to their patents so they wouldn't go under and die.

you dont seem to really understand how things actually work. if the cpu is the cause of low framerates then it is a limitation aka bottleneck. in that particular game its a massive bottleneck.   

Correct, it looks like Thief is a little more dependent on the CPU than other games. Yes the CPU becomes the bottleneck but not in the sense that it's holding back the GPUs. If that were the case you would see the GPUs struggling to hit 100% usage while the CPU was maxed out. Some games the performance gap is even greater between AMD and Intel CPUs. Here's another example:
 
Civilization V CPU comparison
 

First make sure the motherboard supports NVIDIA SLI and if so adding another GPU will cause you to have a performance increase from a single GPU. Obviously the better your CPU is the more framerates the GPUs can push.

Sprinx
It would be really helpful if you answered the questions posed by lephron:
 

lehpron
There is no simple 'yes' or 'no' because we all have different system configurations and play different games.  This is going to require a lot of thinking on your part.

1. What graphics cards are you coming from?
2. What is your monitor resolution and do you plan on upgrading?
3. What games do you play or plan to?
4. Does you mainboard support SLI to begin with (does it say SLI support on the box/manual or on the board itself anywhere)?

I think it would also be good to list your system specs, too, mainly your current graphics card, your motherboard model, and your monitor.
 
I have a friend who has an MSI board for his AMD 6-core that he bought a few years back, and it does not support SLI at all, only CrossFire. It could be that your board doesn't even support it, but we won't know until you check.

1) GTX 760 SLI
2) 1440p
3) Cant really list all out.
4) Yes, my mobo can support SLI. Its M5A99FX PRO 2.0
 
what i want to know is:
 
For eg i7 4790 will run this "X" cpu intensive game at 50FPS with a single 980 and 80FPS with SLI 980..
 
And...
 
Fx 8350 will run this "X" cpu intensive at 38fps with a single 980..will adding another 980 increase the performance?
 
i just dont want it to stuck at 38fps.. even adding another 980 to have the game running at 40-45 fps is considered a performance increase to me. Because the whole point is i wanna get the best out of my Fx8350 and "no changing of CPU".
 

I've had multiple setups with FX-8350s and anything from Xfire 7850's to 290's. Currently running an EVGA GTX 970 1.0 and love it. It kills SLI GTX 770's! That 4GB Vram is great for games like thief and bf4 that can use over 2GB at 1080p on Ultra. 
 
Right now my FX-8350 is at 4.9ghz on an H100i @ 45c load, 24c idle. One of the better chips I've gotten, it's stable at 5.1ghz but I don't like the amount of voltage I have to apply. What I've noticed running SLI with these chips is a hardline to getting better frames and eliminating stuttering. In my experience, you need to clock it up to roughly 4.5 - 4.6 to avoid "bottlenecking" issues. I noticed it heavily with my GTX 760 SLI setup, at 4.3 - 4.4 I was seeing some frametime issues, stuttering etc. OC'd to 4.7 and it went right away, was pretty happy with it. Sold the system and went single 780 and i5-4570, liked that too but sold it =P Then FX-8350 and R9 290, really liked that, Mantle gave super smooth frames in BF4. Ran out of time to play - kids hah! - and sold that to get an Asus ROG G750 w/ GTX 860m. Maxwell 1.0 was so impressive I built another system for the GTX 970. So in all, yes, I suppose you can call it "bottlenecking"; a nice Intel i5 or i7 will ALWAYS get you higher frames in games. Does that necessarily mean it's "bottlenecked"? There are many posts and reviews out there that dispute and refute this, I personally noticed it using stock and lower OC'd 8350s which then got better at higher clocks. 
 
Your mobo is fairly nice, good power phases, I've clocked FX chips up to 4.7-4.9 on that same board. Just takes some time. Maybe spend the money on an H100i and OC higher, see how it goes. If it really doesn't work for you then at least the money isn't wasted as you can still use the cooler in the future for an Intel rig. Hope this helps. 

markd76
Total n00b question here, but screw it. I'm going to ask it, anyway: How is a 4 core CPU better than an 8 core CPU? And why does it cost twice as much? Flame on. 

because games usually need less than 4 cores and they need those cores to be fast. Intel is on another level compared to AMD when comes to core performance. that is why in most cases even a Haswell i3 will match or beat an 8350. even in the handful of games that use more than 4 cores will still have the 4790k and even 4690k on top. a 4790k is the very best overall choice for a higher end gaming pc that will use one or two gpus. only someone ignorant about hardware or too lazy to swap cpus would go with a high end SLI setup with an 8350. 

i3 looks better in games compared to the 8350.  AMD should stop making cpu's

Hey noobs  Stop defending AMD Cpus, We all know that Intel is better dosent matter what,   Its just how it is, Cant do annything about it,   Its a reason why  Both AMD CPU,s and GPU,s  is Cheaper than Intel and Nvidia,     + that 8350 is not a 8 core CPU its actually a quad core 4 cores CPU   Intel 5960X  is a True 8 core 16 threads CPU,  Whit haswell tech    Im at 4960x atm whit 4 way sli 780 Ti Classifieds, + 4 way sli Titans  Going to change to 5960x and 900 series Titan 2 or 980 TI or what its going to be called Owned all enthusiast platforms from intel,  I did see from years back that amd never had a chance to deliver the same amount of power,

Finally! Someone tested SLI GTX 980 setup with FX8350 vs I7-4930k. No longer need speculation.  I dont really see huge bottleneck with the FX8350 980 SLI setup. It just performed 10-20% weaker than I7-4930k during some gaming scenarios. In some gaming scenarios above, you can even see that the FX8350 runs better than the 4930K.  And not to mention, the tester is just using the FX8350 at stock speed.
 
 tweaktown.com/tweakipedia/55/amd-fx-8350-powering-gtx-780-sli-vs-gtx-980-sli-at-2560x1440/index.html (cant post link yet so yea)
 
This is the conclusion of the tester:
"Let's break it down to price: AMD FX-8350 CPU and GIGABYTE 990FXA-UD3 are $179.99 and $139.60, respectively. This is a total of $319.59.
 Comparing this to the Intel setup, where the Core i7-4930K chip and ASUS Rampage IV Black Edition are $578.99 and $473.99, respectively. This is a total of $1052.98.
 
So, the AMD setup is $319 and the Intel setup is $1052 - this makes the Intel setup 329% more expensive. Yes, over 300% more expensive. For 300% more cost, we're not getting more than around 10-20% more performance. This is where you really have to think about the money you're spending. Sure, you might not have gone for two GeForce GTX 980s in SLI, and opted for the Intel processor, spending an additional $600+ on the Intel setup. But why?
 
For the money saved on the CPU and motherboard combo, you could purchase yourself an entire second GPU. This second GPU will provide far more noticable performance in your games, compared to spending it on a CPU.
 
If you were multi-tasking with your PC and using it for rendering, or video editing, or something CPU intensive, then of course - Intel is the clear winner. But for gamers, AMD is a super cheap, but awesome performing alternative that even on GTX 980s in SLI, can kick a huge punch in performance, for budget-minded gamers."