4th Gen Intel I7-4770 @3.4Ghz question.

I just got a new Lenovo with this CPU, nice machine. Came with Win 8 which is fine.

When I run the Windows 7 Task Manager (just figured out you could do this), Performance tab, I see 8 CPU graphs. I thought this was a quad core. Does it actually have 8 cores or is it a quad core with 2 logical processors per core?

I can't seem to find any good info via Google.

📎W7TaskManagerCPUs.png

it's a quad core with hyperthreading, and so it has 4 real cores and 4 virtual/ logical cores too so that's why it shows 8 cores.

http://ark.intel.com/products/75122/

here's some links about hyperthreading that should answer all your questions.

http://www.intel.com/content/www/us/en/architecture-and-technology/hyper-threading/hyper-threading-technology.html

 

Hyper-threading works by duplicating certain sections of the processor—those that store the architectural state—but not duplicating the main execution resources. This allows a hyper-threading processor to appear as the usual "physical" processor and an extra "logical" processor to the host operating system (HTT-unaware operating systems see two "physical" processors), allowing the operating system to schedule two threads or processes simultaneously and appropriately. When execution resources would not be used by the current task in a processor without hyper-threading, and especially when the processor is stalled, a hyper-threading equipped processor can use those execution resources to execute another scheduled task. (The processor may stall due to a cache miss, branch misprediction, or data dependency.)

http://en.wikipedia.org/wiki/Hyper-threading

http://lifehacker.com/how-hyper-threading-really-works-and-when-its-actuall-1394216262

http://www.pcstats.com/articleview.cfm?articleID=1302

should mention you can turn off hyperthreading in the bios, it is then seen as just the 4 cores, personally tho i'd leave it enabled because it does make quite a big differences with muti-threaded software that can make use of all the cores like video encoding.

can't remember exactly how much faster those 4 virtual cores make things, but i do remember it was enough to make me notice with my i7 920.

Thanks Terry.

I'm aware of hyper threading and how it works. Much like what we used to call an Attached Processor (AP) back in the 70s when I worked on main frames. I think that's what I meant by a logical processor though that's a bit different.