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Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 1:36 pm
by davorin
Afternoon (o;

As xmas is coming earlier and on a different date than any other year (o;
I intend to build a new system for OctaneRender with Blender on one side and maybe DaVinci Resolve Studio on the other side...

What motherboard did you choose for running a dual or triple GPU setup?

When it comes to available PCIe slots with at least 8 lanes, AMD motherboards are the clear winner...
and all Threadripper CPUs are cheaper than the Intel counterparts, besides offering mostly 16 lanes only...though X399 motherboards are more expensive.

Is there any downside in using AMD on Linux for OctaneRender/Blender combination?
Most problems I have read about is that some software is using a special subset of the Intel instruction set which AMD lacks...

OTOH with an Intel CPU I might use macOS as well due to the Resolve Studio bugs and crashes on Linux (o;

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 7:39 pm
by Lewis
Problem with most AMD boards (except few Gigabyte models for AMD TR4 socket) is that they usually have 4 PCI-E full sized slots in 1,3,5,7 combination, BUT new GPUs usually need more air to breathe (due vent design/airflow) so you can't stack them near each other so in case of triple GPU setup (air cooled) you need to put them with 1 slot apart and AMD has no workstation boards with 7 full sited PCI-E slots like intel has so your options are very limited if you go for triple GPU setup.

For properly Air cooled triple GPU you need to put GPUs in slots 1, 4, 7 which mean that you need to find AMD board with at least 5 full sized slots (usually 1,3,4,5,7) and not for (1,3,5,7).

Also pay attention that many 3rd party GPUs (MSI, Asus, EVGA, Gigabyte...) are now wider than just 2 slots, some even occupy 3 slots but usually new 2080/2080Ti are 2.5 slots so that 1,4,7 setup is mandatory even physically to put them in machine. There is few models which are still 2 slot so those are better option for more cooling.

P.S. In case you are going to custom water cooling solution then all that can be ignored :).

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 8:11 pm
by davorin
Hello Lewis

Thanks for your input :-)

What about those Asis/PNY blower design cards where they blow they air out at ghe back?
They are only 2-slots wide compared to all the other 2.5 slots versions....

Anyway I will start with one RTX first and add later a second RTX....when Nvidia get a new DDR6 supplier ;-)

So compute wise no difference in using AMD/Intel then...

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 9:06 pm
by Lewis
Blower design fans are OK but often very noisy and hot due fan design.

If you are going for 2 GPUs only then no problem whichever deisgn/MB you choose..

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 9:11 pm
by davorin
Well a triple RZX at thos moment would be very expensive this moment....
also as there is no public version yet to see the improvements in octane render (o;

Well noise is no issue...have a full height rack here stacked with Juniper and Cisco network equipment which make more noise ;-)

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 9:19 pm
by Lewis
well noise is no issue if is room where you set render and go out of room but while you are tweaking the scene/materials you have to listen that noise, trust me i had few TitanX with blower fans and it's not fun to listen those at 4000 rpm for few hours :).

As for RTX i have two of those 2080Ti and they work in Octane just fine and they are faster than my 1080Ti around 30-40% and they will be even more fast when Vulcan/RT cores are included in octane so it's even now great option for rendering sicne they use same Power as 1080ti. Sure they are expensive but still less expensive than another PC/more PSU and more Octane licenses ;).

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 9:24 pm
by davorin
No issues with faulty DDR6 RAM as many people complained?

Still no RTX TI available here.....but I will definitively head for them....
guess money is better spent on GPU than CPU so even a 1900X would be fine...

Re: Intel or AMD MoBo Dual-GPU? (o;

Posted: Tue Nov 06, 2018 9:48 pm
by davorin
OTOH when will octane fully support RTX....probably when Nvidia announces faster hardware (o;

The results I've seen so far are three to four times faster than a 1080TI...so far away from real time....
even a 800x480 100 samples preview in blender takes around 1 second....

Dunno how many RTX cards one would need to replay the famous Nvidia Star Wars live demo (o;