New machine NOT using 100% of CPU


New member
OK So I just rebuilt a machine for my render farm. I had been using all AMD machines which work fine, but I was hoping to build something a little quicker for baking GI scenes.

ANYWAY new machine I7-4790K @ 4GHz with 16GB of RAM. The machine runs great except that the CPU never goes above 80% utilization (Rendering screamernet through BNR) even when all of my AMD machines run at full 100% CPU. The end result is that this brand spanking new machine runs at about the same speed as the one it replaced.

I suppose I could just run two nodes on BNR, but I'd like to know if anyone has seen a trick for maxing out the CPU.



Eat your peas.
A couple of years ago, I had an issue where my scenes were taking a lot longer to render through BNR 4 than if I rendered locally. It turned out that somehow my Multithreading setting for BNR had gotten changed to a setting other than Automatic. When I switched it back to Automatic (0), the render nodes on my farm started rendering at full speed again. Like you, I have a mixed cpu farm, and Automatic should make each machine run at its potential. Just to be clear, I'm talking about the Multithreading setting in BNR, not the one in Lightwave. In BNR 4 the Automatic setting was 0, but in BNR 5 I think it might actually be called 'Automatic'. (I should check later to be sure.)

I don't know if that's the problem you're running into but I thought I'd put it out there. Hope this helps.



TrueArt Support
But baking GI cache should be done on single normal LW, without any renderfarm. Then GI cache locked. And then you can send scene to renderfarm.


New member
Baking the cache.

Yeah that's right... Maybe I should have been more clear. I wanted a faster machine that could bake the cache on it's own... THEN be part of the renderfarm after the GI was cached.

It turns out this machine is quite a bit slower than my 8350FX which is running at 4.3 GHz.


TrueArt Support
I would try to render some standard scene (same settings etc), to see how they both behave and compare.. Don't rely just on GI cache baking speed.

i7-4790K should be 25% faster than AMD FX-8350.
But it doesn't mean that it has to be.
In some cases it might be, in other it might not be.

One rendering 60 seconds, other one 75 seconds. For fast things quite not noticeable difference..


New member
So my i7-4790k scored a 10885
and my FX 8350 scored a 9682

It seems that the machines are pretty much dead equal, sometimes the intel machine is faster, sometimes the AMD machine is faster. I can't tell what specific operation gives one or the other the edge. When I get a chance I'll do some standard LW tests to see if I can figure it out.


Pixel Mage
A trick I use all the time to speed-up the radiosity cache pass is to turn off reflections, refractions and raytrace-transparency on the render tab. then turn them back on after it's done and locked. it looks identical for the majority of scenes (I've had only one exception where I needed to turn on reflections)


New member
Well I found a way to fix the problem...
This new machine will be relegated to the render farm.

I built a shiny new I7-5960X 16GB of DDR 4 and an SSD drive.

Now THAT is the kind of speed I was hoping for. Calculating GI it's almost twice as fast as the brand new 4790k.

It was expensive but now I'll get this job done on time.

Thanks for all your input.
Top Bottom