New 2017 27" only using Dual Cores to render?

[davetwo]

in Cinebench I ran a test after finding my new 27" imac not so quick to render in Cinema 4d and found that it only reads as having 2 cores (4 threads). I've bought it as a quad core machine.... what's going on????

 

[T'hain Esh Kelch]

Where do you see that it only uses 2 cores - Cinebench or Activity Viewer?

 

[davetwo]

Cinebench (and when the machine is listed in Team Render in Cinema4D).Screengrabs attached

 

[joema2]

in Cinebench I ran a test after finding my new 27" imac not so quick to render in Cinema 4d and found that it only reads as having 2 cores (4 threads). I've bought it as a quad core machine.... what's going on????

This is probably a bug in Cinebench, as your i5 obviously has four physical cores. Note they report 2x the threads per core for both i5 and i7. This only applies to i7. They probably forgot to report it differently for hyperthreaded vs non-hyperthreaded CPUs. You can examine what Cinebench actually does by watching with Activity Monitor. Start up AM and select either Window>CPU Usage and/or Window>CPU History, then run Cinebench. This will show what's happening on each core. Cinebench is probably using all cores but reporting it incorrectly.

 

[T'hain Esh Kelch]

Check the usage in Activity Monitor. Cinebench is known to report the wrong number.

 

[EugW]

This is probably a bug in Cinebench, as your i5 obviously has four physical cores. Note they report 2x the threads per core for both i5 and i7. This only applies to i7. They probably forgot to report it differently for hyperthreaded vs non-hyperthreaded CPUs. You can examine what Cinebench actually does by watching with Activity Monitor. Start up AM and select either Window>CPU Usage and/or Window>CPU History, then run Cinebench. This will show what's happening on each core. Cinebench is probably using all cores but reporting it incorrectly.

Right. The 7600K only has 4 threads. It's 4 cores for 4 threads, not 2 cores for 4 threads, so it's a bug.

 

[davetwo]

Yeah - the activity shows all 4 cores. Must be a bug.
Still surprised by the low score though ... it comes in around 615... substantially less than my 2016 MBP (around 730).