Nasty surprise. Carrara 8.5 on Yosemite (OSX) vs Win Xeon CPU

homey_jay

I use a Dell quad core xeon CPU (2.7gHz, around i think) with 12gb RAM for just straight rendering on C8.5 (no animation). Im pretty happy with it but I'm not a huge windows fan (never have been) so finally I went out and got an iMac 27 with an i7 cpu 2.97, 8gb RAM.
I updated it to Yosemite as soon as I got it and installed C8.5 immediately.
My problem started when I rendered a scene on the Mac that I'd previously done on the Xeon. It just took so long!
When it was finally done, i looked at the elapsed time and it said 6min 45 secs. I re-did the render on the Xeon and got a time of 1min 10secs!
Just to recap, same scene, same settings, same everything:

Xeon : 1min 10 secs
Mac i7: 6min 45secs

I've checked EVERY setting in the Carrara document and setup and they are the same on both machines.

Is this right? Could it be a Yosemite issue?
Have I flushed my cash down the toilet - I honestly thought these machines would be similar in performance!

MarkBremmer

It's the quantity of cores and not the gHz. I still am using a Mac tower dual quad core for my 3D work for just that reason. (That and that it's loaded with RAM and I upgraded the GPU to offload rendering for my other 3D and Video needs)

However, you can network them together and have a mini-render farm. You might as well use all of the power you have sitting around. I'm not running a blended PC/Mac render farm in my studio but Eric from Digital Carvers Guild is and hasn't had any issues with it that I know of.

homey_jay

Actually I think i may have solved the problem.
i loaded a couple of images and found that PC version is not rendering to the same level of accuracy that the mac version is!
Mess with the antialiasing, object accuracy and shadow accuracy and the image on the PC will fall to pieces very quickly. On the Mac, its all much more subtle. As you reduce these settings, the speed goes up dramatically but the quality doesn't fall away by much at all.
It's not visible on every image but overall, the render quality on the Mac seems to be better for the images that i'm rendering at least.

Not looking to start a flame war, just talking about my work and nothing else.
it's strange though...

MarkBremmer

Computers were designed to drain bank accounts and increase blood pressure. In that, they have always succeeded admirably well.

evilproducer

homey_jay said:

Actually I think i may have solved the problem.
i loaded a couple of images and found that PC version is not rendering to the same level of accuracy that the mac version is!
Mess with the antialiasing, object accuracy and shadow accuracy and the image on the PC will fall to pieces very quickly. On the Mac, its all much more subtle. As you reduce these settings, the speed goes up dramatically but the quality doesn't fall away by much at all.
It's not visible on every image but overall, the render quality on the Mac seems to be better for the images that i'm rendering at least.

Not looking to start a flame war, just talking about my work and nothing else.
it's strange though...

There are also some things you can do to optimize 64 bit performance. For instance, DAZ Spooky has said that you should go into the Preferences and turn off Texture Spooling under Imaging and Scratch Disk (I believe).

evilproducer

And yeah, as Mark says, if you have a spare computer, use network rendering. It can even be useful for complex still images, not just for animations, though that is where I get my real benefit.

One note about network rendering: If you have plugins or scenes with custom leaf shapes, such as HowieFarkes scenes, then those need to be installed on the node machines as well as the host. No need to worry about that with Content and runtimes though.