Does the i7-920 have four or eight cores?

By H3llion ยท 7 replies
May 8, 2012
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  1. Is the i7 920 8 core CPU? I know that it says that it has 4 cores and HT which means each core counts as 2 therefore 4 > 8 cores. But is it really an 8 core CPU or would you still call it a quad core?
     
  2. MrBlkfx1

    MrBlkfx1 TS Evangelist Posts: 857   +205

    Wouldn't It still be considered a QUAD core? the threads do not count as actual cores. Maybe someone with more knowledge on the matter will chime in. I am interested to know myself.
     
    jobeard likes this.
  3. LNCPapa

    LNCPapa TS Special Forces Posts: 4,200   +479

    It's a quad core CPU - just like the 970 and higher procs are NOT called 12 core CPUs even though they appear to be capable of executing 12 simultaneous threads. In fact, you can only expect 20-30% the performance of an actual core from hyperthreading on applications that can actually use them.
     
  4. slh28

    slh28 TechSpot Paladin Posts: 1,703   +171

    I'm not an expert but here's my understanding: It's a quad core CPU because there's 4 physical cores but HT makes the OS send 2 sets of instructions to each core, so applications recognise 8 threads in total. It's not the same thing as a true 8 core CPU because when two threads are running on a single core, the number of execution units, cache, etc. are split between those threads.

    Here's an analogy: a true 8 core CPU is like having 8 workers and a 4 core CPU with HT is like having 4 workers but giving them two things to do at the same time. You're not going to get double the productivity from the 4 workers but if they're good at multitasking then you might get a 10-20% increase in total productivity.
     
  5. Razer

    Razer TS Booster Posts: 126   +14

    physically it's a quad core, but since it has 8 threads so technically it can perform just like 8 core CPU..
    based from threads (from other forum) and articles I read.. it's still considered as quad core CPU..
    but, I'm not expert on this
     
  6. captaincranky

    captaincranky TechSpot Addict Posts: 13,564   +3,050

    As I imagine it, (and "imagine" is exactly the word most appropriate), there are 4 discreet cores in the i7-920. However there is redundancy in many of the logic circuits. When there is excess data to be processed, the main core is tasked to shunt some of it to the duplicate circuits.

    Perhaps picture something like some of the cars stuck in traffic on the same highway, being allowed to pass on the shoulder of the road. (Best analog I could come up with :confused: ).
     
  7. Touchtech

    Touchtech TS Rookie

    Well, this is only my opinion...(I have to say that )
    I build computers , but I'm not technically knowledgeable enough to give my 2 cents based on different cores and threads and such .....I do know this ..a quad core cannot he compared to an 8core based on how many threads and such ...because qhen dealing with an 8 core processor....dont they operate at a higher speed because of all of the threads that they can multiply Into?????Of a quad core can be considered an 8 core because of the quality and separate threads I guess that they can operate with ..it still wouldnt be equivalent to what the actual 8 core can dish out right???? Or is it just me ??
     
  8. jobeard

    jobeard TS Ambassador Posts: 11,800   +1,255

    Threading is intended to avoid WAITING a core. The tread runs until:
    • an I/O event occurs
    • the tread timeslice expires
    When thread A goes to 'wait', thread B runs to keep the core active.

    HT extends process threads into the kernel space to allow the above to work efficiently.

    SO: a quad CORE processor with HT will support 2x4=8 concurrent HT.
     

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