intel i7 5820K CPU Mandatory Questions before Purchase

[Ragahv]

Hello i wish to buy a i7 6 core and 12 threads processor but i have some questions before i buy it.

When i navigate to msconfig using the run start menu, in windows 8 or 7, i go to the BOOT TAB, then i go to the Advanced Options TAB. I will want to check for the number of cores used by the processor. So there is a check box located the the very left top of the screen which has a label of:
"Number of Processors". If i check that, and i have the intel i7 5820K 6 core cpu with 12 threads, will i see 6 cores or 12 cores?

Also is the intel i7 5820K a power saving cpu like the intel quad core i7u/m?

The problem is that when i hear about the 6 cores i think they are actual physical cpu's on the cpu. Sometimes they are not and they are managed virtually or logically. Threads are logical arn't they?

12 threads means that each cores has 2 threads each. so in msconfig if i have 6 physical cpu's and i see 12 means that each of the 6 cores have 2 threads am i correct? if i am not please correct me.

Its something that is hard to understand as i am not a computer expert but i know there are technical people in this forum who can answere this. Im sure this is not a silly question.

- Right now i own a laptop with a i7 quad core cpu with 4 physical cores and 4 logical cores on top integrated inside the cpu. I am wondering if my laptop actually has 4 physical cores and 4 logical cores or am i just confused? because on my motherboard i have ONLY ONE CPU and that cpu is known to have 4 cores NOT CPU's. Im thinking that intel may of changed the way they make processors. Maybe its a power saving one. Can you please also explain what 12 threads means and whats the differance between cores and cpu's?

 

[kanewolf]

Your laptop probably has 4 physical cores and intel Hyperthreading (4 logical cores). The 5820K is similar. It has 6 physical cores and 6 logical (hyperthreaded) cores. You can disable hyperthreading in the BIOS if you don't want the extra phantom cores. The purpose is to allow more resources for the operating system to schedule tasks against. If there are 6 cores shown to the OS it will attempt to run up to 6 things concurrently. If there are 12 cores presented to the OS it will attempt to run up to 12 things concurrently. The hardware takes advantage of inefficiencies in the software to squeeze the extra 6 tasks in. It can't get 100% improvement. There is usually a 10% to 25% total improvement.

 

[photonboy]

Hi,

1) CPU test: https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool-64-bit-

2) 12 threads:
Open Task Manager (CTRL-ALT-DEL)-> Performance-> CPU-> (if one graph then right-click and choose "change graph to-> logical processors"

*Open Task Manager, THEN run the CPU diagnostic and during the test you should see all TWELVE graphs running at near 100% usage. You can also verify the CPU Turbo is correct under "Speed" below the graphs. For example, if 4.0GHz it will be LOWER in idle but should be pretty close under load.

3) Laptop:
You can go to the INTEL site easily by Googling the CPU model. If you see "4C/4T" then it's four physical cores with no hyperthreading.

4) Cores vs CPU's:
All CPU's were originally just one core. When we got "dual core" it basically was TWO CPU's next to each other with a way to manage sending data to the appropriate core.

Multiple CPU's are very rare and generally only for Servers. So it's a single CPU which has multiple cores.

5) Hyperthreading?
When a CPU is "hyperthreaded" then each PHYSICAL core is simply processing data during wait states it normally would be idle.

*It's like eating candy using your right hand, you finish chewing but haven't brought more candy back to your mouth yet... however your LEFT hand has some candy ready so as soon as you stop chewing the food your RIGHT hand gave you the LEFT hand feeds you.

**Hyperthreading can increase processing amount by over 30% in ideal situations where the software is well optmized (Handbrake video converter at times).

Cores/Threads:
So to summarize the i7-5820K:
a) SIX physical cores
b) each core is hyperthreaded
c) Task Manager shows TWELVE threads
d) Every 2nd graph starting with the FIRST graph in Task Manager is a physical core
e) Every 2nd graph starting with the SECOND graph in Task Manager is the hyperthread portion which is NOT weighted equally (so the average is actually incorrect). As I said earlier roughly 30% benefit possible.

f) Example:
Core0,
Core0 HT,
Core1,
Core1 HT, etc..

f) *so as per your question "will i see 6 cores or 12 cores" the answer is there are SIX cores but with hyperthreading we summarize as saying "TWELVE THREADS" so again you will see twelve graphs in the CPU section of Task Manager.