3x or 4x SLI

From what I have read for 4k resolutions you are best off with the AMD R9 290X in crossfire. 2 or 3 depending on your budget should be fine. The Nvidia's seem to have ~5% lower frame rates at 4k resolutions.

Good info on mixing 295x2 and 290x in same rig.

Who'd a thunk.

Those are impressive benchmarks as far as scalability goes. Is that likely just a result of AMD having better multi-gpu support for their drivers? Definitely gives me something to consider.

I had previously been set on another nvidia card this time because I was looking forward to buying a g-sync monitor. Specifically the Acer 4k that was recently announced (still unreleased). From what I've heard, g-sync is pretty impactful for gaming by making the frame rate appear smoother by eliminating tearing.

I know that adaptive-synch is coming as well but it's a bit behind and I haven't seen an 4k displays announced that will use the technology (although I'm sure they will come).

The price difference between going AMD and nvidia are not my most pressing concern though. I'm also just generally concerned with the practicality of getting a 4th GPU. I understand the performance gains from adding a 4th will not be as significant with many games. That's ok as some games will still be able to make use of it (Crysis 3 seems to scale well with 4 GPUs) and it wont be a complete waste.

My main concern are situations in which having extra GPUs may result in worse performance and an overall less smooth gaming experience.

Edit: I am planning on going with the ASUS Rampage IV Black Edition X79 for the motherboard and the 4960x for CPU. I have heard that this board is ideal for multi-gpu setups so I decided to go with that rather then a newer board with Devil's Canyon.

As a secondary question: is this the best RAM Digital Storm offers?

32GB DDR3 2400MHz Corsair Dominator Platinum DHX (Extreme-Performance)

Edited by DolanRy11771 - 29 Jun 2014 at 5:08am

Originally posted by danjw1 Of course it bares saying there is always going to be the next big thing coming down the road (soonish). ;-)

Somewhere on these boards there is a quote, attributed to fstcvc:


"But if I keep waiting for the next best thing, I'll never have anything."


Ultimately, though, it's your choice.             

I think the next gen video cards may be a bit later.  I'm seeing Oct-Nov time frame:  http://wccftech.com/gtx-880-arrive-oct-nov/.  One question I do have, what would be the performance difference between the X99 platform and the Z97 4790K?  Is there any analysis or projections showing this?

Edited by Dax Doomslayer - 30 Jun 2014 at 7:42am

I can't say for sure, testing will tell, but I doubt the newer 6/8 core Haswell E will do much extra for strictly gaming. It might allow higher overclocking for the enthusiast that want to push it if it has the better TIM which has been mentioned.   The faster, 50% better memory bandwidth with the DDR4 ram might help, but looks like an expensive way to go for a small increase in performance.    

But, I could be wrong and time will tell.

Edited by bprat22 - 30 Jun 2014 at 11:43am

Originally posted by Nav bprat22 pretty much covered everything. Quick note, 90% of games actually perform BETTER on a 4770K/4790K as opposed to a 4960X.

The one thing that dissuaded me from going with a 4790k is the mother boards available for it at the moment are not ideal for big multi-GPU configurations. I've heard this is because with a 2011 board there are more PCIe lanes. Instead, the Z97 boards use a PLX (?) chip to give more lanes but also has the tradeoff of introducing a little bit of latency.

I am not that knowledgeable about this but this is what I've found with a bit of researching and asking around. My guess is that although benchmarks for a 3-4 GPU system would be better with the newer boards and the 4790k, that little latency introduced may negatively impact how smooth gameplay is overall. Maybe I am misinformed?

Are there any new boards that are compatible with the 4790k that don't have this problem?

Edited by DolanRy11771 - 01 Jul 2014 at 9:15am

It is true that to get 4x sli with a Z87/Z97 chipset, you need the PLX chip.  The Z87/Z97 only have native 16 lanes to carry the info from cpu to gpus.   It does it by multiplexing, where the chip acts as a super fast switch to send 16 lanes of info across up to 40 lanes, allowing 4x cards to function.   The X79 has native 40 lanes of traffic , so no PLX chip is needed.   With the Z87 Maximus 6 extreme, you get, I believe, x8x16x8x8 in quad sli.   But that's Pcie 3.0 and will work fine.  As far as latency, yes, there has to be some just by the nature of multiplexing, but my understanding is that is is extremely small.    What helps make it small or not noticeable is the fact that in tri and quad sli setups scaling of each card past 2x sli makes the latency irrelevant.   If each additional card added another x2 , x3 etc performance, then maybe it would matter.

The X79 and X99 does have the 40 lanes in native, so i'm not sure if it makes all that much difference.  The X79 Rampage 4 gives you x16x8x8x8 electrcal to each card and the PLX gives you, on some, X8x16x8x8, so latency should be the only unknown, which I've read is very small. 

Maybe Nav , if he's tested it, can say.

Tough decision. 



Edited by bprat22 - 01 Jul 2014 at 9:58am

Here is the Asus product page for the Maximus VI Extreme: http://www.asus.com/us/Motherboards/MAXIMUS_VI_EXTREME/overview/

If you go to the "Support" tab then manual and document you can download the manual. It is 8x/16x/8x/8x in four card mode.