Multi-thread feature in Blender.

Dec. 12, 2005

Since my new PC is dual core CPUs, I confirmed that multi-thread feature in Blender. I am engineer. So, I want to confirm everything by myself (really?). My PC spec is Athlon64 X2 4400+. According to my investigation in the Internet, Blender's multi-threading can be two threading (at this time). Whatever the available number, I am glad to use multi-threading, because Blender is free (open source software).
In the case of single core PC, recent Intel CPU can fake multi-threading by using Hyper Threading function which can be enable in BIOS setting. My old Intel PC was Pentium4, but I couldn't find the setting in BIOS setting.... Anyway, I got new dual PC. I stopped searching the function.

To enable multi-threading in Blender is turning on "Threads" button in the Output panel (See below).


We can confirm that Blender is using multi cores in the task manager. Following image is the screen shot of the task manager.
Wow, really multi !

Executing Multi-threading

Now, I confirm the multi-threading feature by measuring a rendering time in three times in each test cases. And then average them. Since this is easy confirmation, I don't ignore other environmental settings and parameters. Go easy. Test case is four cases as shown as below. I measure a rendering time in the 2 spheres, 8 spheres, 14 spheres and 24 spheres.

case 1 case 2 case 3case 4

The measurement time is not important. That depends on PC spec. Important is relatively difference between single threading mode and multi threading mode. So, please don't point out my PC is slow, or your PC is much faster.

Following image is result of the confirmation. Wow! Multi-thread!
It may be too extreme. Multi-threading became a half comparing to single threading mode. You may think that the PC is dual, so the result is expected. But I think if the Blender code is not appropriate, the result would be different. Now I have confirmed that Blender has good code.
The trend lines has different tilting in this result. That is good.


Now conclusion,
Blender multi-thread feature is useful. I always turn on the Thread button.
(According to investigation in Internet, there is no problem to use this function at this moment.)

Return to Articles Menu.