jura11 posted at 1:15PM Tue, 28 June 2016 - #4274001

bhoins posted at 3:42PM Tue, 28 June 2016 - #4273993

The issue is not just the Processor but the Motherboards.

AMD Motherboards are lagging far behind Intel Motherboards. You are generally looking at PCIe2 vs. PCie3, Slow SATA, no M.2 location, etc.

For Iray (and Superfly, for that matter) the 980Ti is still the best bang for the buck. If you can find a 1080, and can get Iray Drivers for it, then it is a slight improvement over the 980Ti but I am not sure it is worth it yet.

Personally I would spend no more than half your Video Card Budget and get one or two 980Ti then hold out for the 1080Ti.

Hi there

On this I would agree,but newer AM3+ Motherboards supports M.2,SATA is still not the best,but still OK,unless you are do lots of transfers between the drives PCI-E 2.0 is bit slower than PCI-E 3.0,mainly in gaming,in rendering I'm not sure if it will make any difference

https://www.pugetsystems.com/labs/articles/Impact-of-PCI-E-Speed-on-Gaming-Performance-518/

And motherboards which supports M.2 are here few

http://techfrag.com/2016/02/01/usb-3-1-and-m-2-finally-make-their-way-to-the-socket-am3-motherboards/

http://www.asrock.com/mb/amd/fatal1ty%20990fx%20killer/

GTX1080 is still not supported by IRAY as CUDA Toolkit is not released and most of SW is still not support new CUDA and looks like new CUDA will be released sometimes in July/August and Otoy(Octane Render) have seems issues with new CUDA as is not working as should,due this I would get as you are said GTX980Ti without the questions,but GTX 780 6GB is still better card for money if you can find that card,I've compared this card to my Titan X and this 780 6GB has been very similar in rendering like my GTX Titan X

Hope this helps

Thanks,Jura

You are looking at about an 8% to 10% hit between PCIe2 and PCIe3 for Iray, according to NVIDIA. And that presumes you have the same number of lanes. (Not even close with a high end board and new i7 Processor if you are using multiple cards.)

Note I am not saying you can't use an AMD board and AMD processor, just that for optimum performance they have fallen behind the Intel Boards.

Also note that Broadwell was not supposed to have a Quad Core (Skylark is not Broadwell) so you are comparing a minimum of 6 cores vs. the AMD 8. The AMD 8 core only has one FPU per two cores and while that doesn't matter, in general, for gaming, rendering is, usually, Floating Point math.

With the Iray 2015 that is in DS 4.9.2+ the 980Ti does outperform the 780Ti. It was one of the bug fixes in that build of Iray.