Digital Art Zone

Garstor,

Not really hyperthreading. They have 12 integer cores and share a floating point unit between each pair of integer cores. Much better design than Intels hokum with using wait states and claiming twice the power.

Joe

Garstor - 15 July 2012 08:43 AM

On that note, I’d love to see Carrara implement an affinity mask feature for CPUs. That way you could “give” X-number of cores to the Carrara process and reserve Y-number of cores for the rest of the system.

A setting in Carrara would be nice. I set affinity through the task manager.
Apologies if you already know this but;
right click on the Carrara process and select set affinity.
Just uncheck which core(s) you want to release.
You can do this mid render if you want and then re-check it when you want to give it full bore.
A good thing is that Carrara will still use the cores when they are available but will release them when other processes want them.

Personally I prefer to leave my render machine to render alone as much as possible but there are a few occasions when I need to use software that is not on my laptop or on my second string PC. If you are rendering on a server clearly that is not an option.

The obvious question…how much speed improvement compared to a “normal” PC with 4 cores/8threads; say i7 2600 3.4GHz for duplicate render?

My guess is 24 vs 8 cores is a little under 3x faster to account for overhead…and optimum size of render square tile size (assuming CPU speed is same and RAM sufficient)

Do you have any data?

DougS - 15 July 2012 01:26 PM

The obvious question…how much speed improvement compared to a “normal” PC with 4 cores/8threads; say i7 2600 3.4GHz for duplicate render?

I must confess my deepest shame for not having thought of this myself!

I’ll get this remedied later today…find an older scene on my other machine and use the statistics tab from the Render Room to compare both boxes results.

More to follow after the experiment!

RoguePilot - 15 July 2012 12:21 PM

A setting in Carrara would be nice. I set affinity through the task manager.
Apologies if you already know this but;
right click on the Carrara process and select set affinity.

True! That is an easy option to forget about. It is also controlled by the OS rather than the process; so it doesn’t persist between process lifetimes. I’ll try to remember it though when I get a long-running physics animation calculating…

VERY surprising results in my “render race” between the two machines.

I posted the MSInfo32 stats for the new AMD server earlier in this thread. Here are the stats for my older Intel machine:

OS Name Microsoft Windows 7 Ultimate
Version 6.1.7601 Service Pack 1 Build 7601
System Type x64-based PC
Processor Intel(R) Core(TM) i7 CPU       870 @ 2.93GHz, 2934 Mhz, 4 Core(s), 8 Logical Processor(s)
Total Physical Memory 7.99 GB

Here is the scene I was rendering: http://www.flickr.com/photos/garstor/6981911339/in/photostream

Scene Render Settings
Width   1680
Height   1050
AntiAliasing   Best
Object Accuracy 0.5
Shadow Accuracy 0.5
Sky Light   True
Indirect Light True
Light Thru Transp.  True
Lighting Quality Excellent
Accuracy   1
Irradiance   One for all frames
Tile Size   16

Caveat: on the new machine, Carrara could not find the Lana Elite texture or bump maps for Victoria (so she had a zombie/undead pall to her…poor thing!) or the texture for Michael’s jeans. I am not sure if this affected the render times.

Old Intel Machine
Start Time:  8:15:49 AM
End Time:  12:24:36 PM
Elapsed:  4:08:38

New AMD Server
Start Time:  10:14:21 AM
End Time:  1:49:40 PM
Elapsed:  3:35:10

Surprisingly close! I think that this shows Intel chips have better overall computational strength. However, bang-for-buck, AMD gets my vote…I simply wasn’t willing to spend the $$$ needed for a 2-socket hex-core Intel machine.

If anyone thinks I did something wrong here, I’m happy to re-test with further suggestions (at least until I pave over the Intel box…I’m thinking of getting rid of its SSDs as it keeps blue-screening on me).

so you gain 30 mins. - boy I don’t know - don’t seem right to me

bigh - 16 July 2012 01:53 PM

so you gain 30 mins. - boy I don’t know - don’t seem right to me

Yeah, not intuitive…I am guessing something is amiss. Perhaps some power setting (I did set Windows to High Performance though)...maybe something I missed in the BIOS. This is the first AMD machine I’ve ever owned.

Hi, I’m not sure about the total render time but try measuring from when Carrara actually starts dsplaying the image, it may be interesting.

I think some things are still single threaded sometimes. (Could be wrong).

And did you have any verification that all 24 cores were being used to render?  I could be wrong but thought I read somewhere a couple years ago that Carrara was limited to perhaps 8 or 12 cores (on one machine, not across multiple PCs as a render farm).  This may need some investigation. May be why no more than 8 tile squares of render show at a time?

DougS - 16 July 2012 08:31 PM

And did you have any verification that all 24 cores were being used to render?  I could be wrong but thought I read somewhere a couple years ago that Carrara was limited to perhaps 8 or 12 cores (on one machine, not across multiple PCs as a render farm).  This may need some investigation. May be why no more than 8 tile squares of render show at a time?

I seem to remember reading about an 8 thread limit somewhere as well, but I’ve been looking unsuccessfully for a reference before posting.

Kendall

DougS - 16 July 2012 08:31 PM

And did you have any verification that all 24 cores were being used to render?  I could be wrong but thought I read somewhere a couple years ago that Carrara was limited to perhaps 8 or 12 cores (on one machine, not across multiple PCs as a render farm).  This may need some investigation. May be why no more than 8 tile squares of render show at a time?

I was watching the render progress frequently. There was most certainly 24 distinct “render tiles” at work (remember I used a size of 16x16…and Carrara only puts numbers in them when they are 48x48)..

Does task manager show all 24 cores running at 100%.??

I have noticed on some scenes with IDL / GI enabled Carrara will crawl along and use only about 25-35% of your cores, yet if you disable IDL /GI on the same scene, it shoots back up to 100%.

I have two Intel 3930K’s networked and over clocked to 4.2ghz, and there is nothing more frutstrating than seeing Carrara not using all of my rendering cores.

Peace,

SK.

swordkensia - 17 July 2012 08:13 AM

Does task manager show all 24 cores running at 100%.??

I have noticed on some scenes with IDL / GI enabled Carrara will crawl along and use only about 25-35% of your cores, yet if you disable IDL /GI on the same scene, it shoots back up to 100%.

I have two Intel 3930K’s networked and over clocked to 4.2ghz, and there is nothing more frutstrating than seeing Carrara not using all of my rendering cores.

Honestly, I didn’t watch Task Manager. I am quite sure that I do not have IDL / GI in that scene though.

In your scene settings you state.

Sky light - true

IDL - true

Lighting Quality - excellent..

Those settings would indicate that you DO have IDL / GI enabled for your scene..unless I am mis-undertsanding your nomenclature.

Peace,

SK.