I have i7 5820k which is very slow with heavy multi threading.

[eshag]

I have i7 5820k, which runs on MSI or Gigabyte motherboard.

it is very slow with heavy multi threading, It runs half speed as i7 3770k or i7 2600

heavy mem access is very fast for 5820k,

heavy compute task is fast for 5820k,

the application does not use disk or display, only cpu and memory.

I have replaced both cpu and motherboard, with no difference.

[Hans_B_Intel]

Hello eshagam,

In order to better assist you, please copy the report for the Intel Processor Diagnostic Tool. http://www.intel.com/support/processors/sb/CS-031726.htm http://www.intel.com/support/processors/sb/CS-031726.htm

[eshag]

Hi,

The diagnostic tool did not find any problem

I compared the 5820k with i5

i7 5820k 3.3ghz Operation Per Second--> 5.98121e+006

Intel Core i5 760 2.80GHz Operation Per Second--> 3.98747e+006

I suspect that all 6 core will be slow on frequent multi threading swap

---------------------------

--- Testing Processor 1 ---

---------------------------

--- IPDT64 - rev 2.20.0.0.W.MP ---

--- Start Time: 06/20/2015 11:48:36---

--- Skipping Config ---

--- Reading CPU Manufacturer ---

Expected --> GenuineIntel

Detected --> GenuineIntel

Found --- Genuine Intel Processor ---

--- Temperature Test ---

Temperature Test Passed!!!

Temperature = 57 degrees C below maximum.

--- Reading Brand String ---

Detected Brand String:

Intel Core i7-5820K 3.30GHz

Brand String Test Passed!!!

--- Reading CPU Frequency ---

Expected CPU Frequency is --> 3.30

Detected CPU Frequency is --> 3.30036

CPU Frequency Test Passed!!!

--- FSB NOT Supported on this Processor ---

--- Running Base Clock test ---

Detected Base Clock --> 100

Base Clock test Pass ---

--- Unable to retrieve any QPI Link device id ---

..Skipping QPI rate Test..

Skipping QPI rate Test

--- Running Floating Point test ---

Million Floating Points per Second, MFLOPS --> 403.2

Floating Point Test Pass ---

--- Running Prime Number Generation Test ---

Operation Per Second--> 5.98121e+006

Prime Number Generation Test Pass ---

--- Reading Cache Size ---

- Detected L1 Data Cache Size --> 4 x 32

- Detected L1 Inst Cache Size --> 4 x 32

- Detected L2 Cache Size --> 1024

- Detected L3 Cache Size --> 15360

Cache Size Test Passed!!!

--- Determining MMX - SSE capabilities ---

--- CPU FEATU...

[Hans_B_Intel]

Hello eshagam,

The IPDT shows that you have a healthy processor, I would suggested that you check how the application uses multithreading, this does not seem to be a hardware issue but rather something in the way the app runs with more cores and threads.