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Mammoth

macrumors 6502a
Original poster
Nov 29, 2005
938
0
Canada
For example, a 2 Ghz iMac Core Duo would be running at a total of 4Ghz, or is each core at 1?
 

Koodauw

macrumors 68040
Nov 17, 2003
3,952
197
Madison
each core runs at 2.0 ghz, however 2.0 ghz X 2 cores does not mean you have a 4.0 ghz machine.
 

powerbook911

macrumors 601
Mar 15, 2005
4,003
383
Koodauw said:
each core runs at 2.0 ghz, however 2.0 ghz X 2 cores does not mean you have a 4.0 ghz machine.

It's actually better. Right? I mean, it's just not a comparison.

However, isn't have 2 x 2.0GHZ cores better than 1 x 4GHZ core?
 

BlizzardBomb

macrumors 68030
Jun 15, 2005
2,537
0
England
powerbook911 said:
It's actually better. Right? I mean, it's just not a comparison.

However, isn't have 2 x 2.0GHZ cores better than 1 x 4GHZ core?

Not if the main apps you use aren't dual-core aware (such as games).
 

laidbackliam

macrumors 6502
Feb 1, 2006
330
0
powerbook911 said:
It's actually better. Right? I mean, it's just not a comparison.

However, isn't have 2 x 2.0GHZ cores better than 1 x 4GHZ core?

there are probably arguments each way on that debate
 

Timepass

macrumors 65816
Jan 4, 2005
1,051
1
laidbackliam said:
there are probably arguments each way on that debate


well 1 4ghz chip will be faster than 2x 2ghz chips which is faster than 1 cpu with 2 cores going at 2ghz.

Rememeber the dual core chips only have 1 memory modudal on them and the Computer yes will see 2 cores but it still only 1 CPU.

running dual CPU only really gains you about a 25% increase in profmence because the OS and other basic things is going to eat CPU power out of each chip and that ammount is about the same for all CPU. so basicly the loss of Processor power to the OS is 2xgreater in a 2 cpu computer.

and rememeber 1 instuction set can only be run by 1CPU. a 4ghz chip would run that instuction 2x faster than the 2ghz chip and a lot of things require one set of instuctions to be completed before the next one to begin because the need data out of that instuction set to do it.


That being said a 4ghz> 2 CPUs 2ghz> 1 cpu with 2 cores at 2 ghz. Also rememeber this is based on the CPUs them selves being at the same level of effincey for each clock cycle.
 

balamw

Moderator emeritus
Aug 16, 2005
19,365
979
New England
Timepass said:
That being said a 4ghz> 2 CPUs 2ghz> 1 cpu with 2 cores at 2 ghz. Also rememeber this is based on the CPUs them selves being at the same level of effincey for each clock cycle.

How about 1 4 GHz CPU emulating two 2.0 GHz cores? (i.e. Hyperthreading, which is the default state of most recent P4 CPUs.). :p

B
 

Mikael

macrumors regular
Aug 4, 2005
158
0
Gothenburg, Sweden
balamw said:
How about 1 4 GHz CPU emulating two 2.0 GHz cores? (i.e. Hyperthreading, which is the default state of most recent P4 CPUs.). :p
What? Did you even read the Wiki article you linked to? Hyperthreading is not about emulating two cores at half the internal clock frequency, it's about sharing the execution unit resources between two threads.
 

Shamus

macrumors 6502a
Feb 26, 2006
651
0
ghz isnt a very accurate way to measure the true power of a CPU.
 
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