Dual Core vs Quad Core Question...

[ttechf]

Lets say my CPU usage is 40% on a dual core that is 2.2Ghz. Would that mean if I were to get a quad core at 2.2Ghz, my CPU usage would only be 20% or
does this theory not work? Would my CPU be at less than 40% usage at all?


Thank you.

 

[BrightCandle]

Depends on whether its really a dual core. Most dual cores sold today have hyperthreading and hence display to the operating system that they actually have 4 cores. Thus your 40% would represent 80% of 2 cores. Moving to a real quad core such as an i5 would still have the same number of cores displayed to the operating system and hence the usage would appear the same.

Need to know the processor models you are talking about. But hypothetically that is how it works and assuming the program doesn't change its behavior due to the processor change you would see a drop in usage.

 

[ttechf]

Depends on whether its really a dual core. Most dual cores sold today have hyperthreading and hence display to the operating system that they actually have 4 cores. Thus your 40% would represent 80% of 2 cores. Moving to a real quad core such as an i5 would still have the same number of cores displayed to the operating system and hence the usage would appear the same.

Need to know the processor models you are talking about. But hypothetically that is how it works and assuming the program doesn't change its behavior due to the processor change you would see a drop in usage.

Okay, you got me on a technicality. lol. Let's say I have an i5 that does have hyper threading at 2.2Ghz. Lets say I go and grab an i7 also clocked at 2.2Ghz that has hyper threading and both are the same generation, lets just say both are 3rd generation for this example. So going from 4 to 8 logical cores. So hypothetically my CPU usage should cut in half?

Thanks.

 

[sefsefsefsef]

The same amount of work will be done in both situations, so there isn't an advantage to reducing your "utilization." In task manager it might appear that the work is being evenly spread across all the cores, but this is mostly because of thread migration. Having said all that, yes, task manager will report 20% instead of 40%, but like I said, this is a meaningless illusion.

 

[2is]

Actually most dual cores today don't have hyper threading. Only the i3s do.

 

[Zodiark1593]

Actually most dual cores today don't have hyper threading. Only the i3s do.

Not true when you look at laptops, as the mobile i3s, i5s, and some i7s are dual cores with Hyperthreading.

 

[ttechf]

Not true when you look at laptops, as the mobile i3s, i5s, and some i7s are dual cores with Hyperthreading.

I know when it comes to Intel, any i series processor with the exception of like 2% of them are hyper threaded. i3,i5 and i7 for laptops.

Only the i5 on desktops is not hyper threaded.

 

[2is]

Not true when you look at laptops, as the mobile i3s, i5s, and some i7s are dual cores with Hyperthreading.

This is true. I was referring specifically to desktop SKU's

 

[SPBHM]

Only the i5 on desktops is not hyper threaded.

some first gen i5s have HT (i5 650, 661), some lower power newer i5s have HT like the 4570T :biggrin:

 

[ttechf]

some first gen i5s have HT (i5 650, 661), some lower power newer i5s have HT like the 4570T :biggrin:

Yeah only problem is GETTING A "T" series. I've yet to see a place that I can buy them from, lol.

 

[lamedude]

If you use a *nix OS it would be 80%.

 

[BrightCandle]

Going from an i5 to an i7 would make the usage number shown in Windows halve. So long as the program didn't change its behavior when the number of processors changed.