Why are 8 cpu's have more load than one?

if i switch from 1 to 8 cpu’s i have double the cpu load !?

Probably this thread here answers your question. If not, could you give us a few more infos on what exactly you mean?

i have renoise 3.01 64 bit on windows 7 home 64 bit 8 gb ram and i7 processor.

if i load a demo song “sunjammer” and play it i have a cpu load of 4.0 % (8 cpu’s)

if i switch to 1 cpu i have a cpu load of 2.0 !!!

demo song “sunjammer”

Sunjammer’s demo song “I Understand Now” is certainly not the best example when it comes to testing multi-core processing, because it features only a single basic instrument playing within a very simple track set-up. There’s actually very little that Renoise can do there to efficiently spread the load over your available CPU cores.

As taktik’s other post explains, there is some additional overhead required when processing a higher number of CPU cores. In Sunjammer’s very simple demo song, the whole song can probably play quite happily on a single CPU core, so the additional processing required for 8 CPU cores is most likely going to waste.

However, when you have a more complex song, then you should easily begin to see more benefits from the multi-core processing. If you have multiple different instruments or VST plugins playing simultaneously on multiple different tracks, then Renoise will be able to more effectively spread the load over your available CPU cores. You should definitely see a difference between 1 CPU and 8 CPUs in that type of situation.

For example, if I load 8 unique instances of Chromaphone VSTi, with each of them playing a single sustained note on 8 different tracks…

  • 1 CPU = ~37%
  • 2 CPUs = ~22%
  • 4 CPUs = ~14%
  • 8 CPUs = ~11%
    (For reference, I have an i7-3630QM)