[Scippi]

Hey guys me and my mate were arguing about dual cores CPU's, i said that if u have a dual core 2.8 ghz CPU then each core would have 1.4. He said that each core would have 2.8 and not 1.4, that's why AMD dual core processors are call what they're called e.g AMD 5600+ = 2800x2 AMD 6000=3000x2

So which one of us is right? come on please be me please be me so i can just go to him and say HA! ^^

[Joshuashawharvey]

AMD use what is called a Speed Index. This is used to determine it's relative speed compared to Intel counterparts so I believe.

For example lets take an AMD Athlon X2 4600+. The 4600+ is the index, not the actual speed. The actual speed of an X2 4600+ is 2.4GHz.

If you have a 2.8GHz dual core then it will be 2.8GHz per core, not 1.4GHz.

The way AMD label their processors is confusing for many consumers.

Do not confuse the speed index with the real clock speed.

[Daveskater]

It seems your friend will be the one saying "HA!" as he is right, as is Josh. If it's a 2.8GHz as in your example, that means 2.8GHz per core, so 5.6GHz total.

Josh is also right about the speed index, for example I have a 4800+, which means that AMD think it is as good as or better than an Intel CPU with 4.8GHz total. It confuses a lot of people and I never really understood it for quite a while.

[Taima]

Not to throw another question on top of this, but what you're saying is that for me (with my new 7750+) it's equal to an Intel w/ a combined total of 7.75ghz? Which is like an intel dual core with 3.8ghz? Nice lol I never knew that. It also answers my question of why when I go on srtest.com it always rates my processor higher than its clock speed.

[wladicus]

Thanks for the interesting info guys.

[Joshuashawharvey]

Taima: AMD used it as a speed index on their older processors to indicate it's relative speed compared to Intel counterparts, but to my knowledge they no longer do this.

The X2 7750+ is a fairly new processor from AMD, and more than likely gets it's name due to a new architectural design compared to other X2's, and not as a speed index.

[Daveskater]

You may be right there Josh, iirc the 50 part is the energy efficient models or something

[Sup2a]

Also to add on this, having dual core processors does not mean both of them combine to create a "supercore" meaning a dual core processor with a rating of 2.0ghz does not mean a total of 4 usable ghz, dualcore means the cores run "independently" as such

[Taima]

Originally Posted by Sup2a

having dual core processors does not mean both of them combine to create a "supercore" meaning a dual core processor with a rating of 2.0ghz does not mean a total of 4 usable ghz, dualcore means the cores run "independently" as such

Yeah but even though they're separate don't they share the load? Hence making like a sort of supercore lol

[Sup2a]

yes in certain cases, like many games now take advantage of dual and quad core processors, however some do not, only relying on one core, however another core my be in charge of another application running in the background, same with some applications, and even though the cores are sharing the load they do not merge as such, i understand what your saying and for sure it makes it a LOT faster, but its not the frequency as such its just the power and speed of having multiple cores that gives dualcore a major advantage, so in some cases yes you would have a super processor, however in other cases where applications only use one core, probably not so much, but i certainly see what you saying

[Scippi]

Ty for all the responses guys, and awww lol guess i'm gonna have to try and hide this thread from my friend then
When dual cores first came out, i was reading an article about dual cores CPU's and i'm sure it said somewhere that the reason dual core CPU's were invented so they can be more efficient and not have as many overheating problems as single core CPU's but how exactly is having 2 cores with the same clock speed more efficient and cooler than a single core apart from the fact that the 2 cores can share work loads so either of them will be overloaded?

[Joshuashawharvey]

You are right about them being more energy efficient, but you are missing the point.

What they are trying to say is a dual core at 2.4GHz for example, would be more energy efficient than a single core at 4.8GHz. The thermal and power output for a processor running at 3.8GHz is absolutely ridiculous, let alone one running at 4.8GHz. Just think back to Pentium 4 Prescott. The Pentium 4 3.8GHz has a TDP of 115w even when running with a 90nm fabrication process. An AMD X2 4600+ 2.4GHz (which would equate to a single core running at 4.8GHz) running on a 90nm fab has a TDP of just 65w.

It would also be more energy efficient than having two independent processors running at the same speed. This is due to sharing the same IC, buses, or in some cases, such as Core 2 Quad, even the CPU die.

[Albert Lionheart]

Go quad - then you have in theory 4 cores all capable of running at the rated speed. My Q9300 runs in theory at a total of 10Ghz but as the man said, it doesn't work like that!

[Ukkonen]

Some AMD Dualcores let you to choose what to run with which core, and it comes really handy sometimes when it is non balanced or you do something else. I often dedicate one core to work and one to entertainment

[Joshuashawharvey]

Ukkonen: You can do that with any multi-core processor by setting the Affinity to a particular core under the Processes tab in the Task Manger

[Taima]

Thanks for the understanding there Sup2a. Yeah when I made that statement, I was thinking in terms of gaming (as a gamer myself lol) and yeah like you said many do take advantage of dual or quad cores. I doubt they make games that support less than 2 cores anymore.

btw Joshua, for some reason I never realized the reason that they didn't make super fast single core processors was because of wattage/temps even thought I knew that multicore processors are more efficient. Go figure :P

[Joshuashawharvey]

Well you learn something new every day I guess

There are many advantages of multi-core processors over single core and using more than one processor on the same system, such as:

They are much more efficient when used with applications which take advantage of more than one thread. There are hyperthreading single-core processors which will allow a CPU to accomplish two threads with a single CPU, but an independent physical core will perform better than a "virtual" core as it were.

Even when running software not programmed to utilise more than one core, multi-tasking is much more efficient. Therefore you have room to perform CPU intensive tasks such as antivirus scans, encoding or games whilst performing other tasks without any noticeable slowdown. A single core processor would probably grind to a halt on the tasks I mentioned, let alone perform other tasks simultaneously. Even if that single core was say 6GHz, there still wouldn't be much room for other tasks without any noticeable slowdown. It would just get the single task done quicker than one with a lower clock speed.

Cache can run at a much higher clock speed than if you were to use two seperate processors due to cache coherency. This simply means that the cache for all cores is stored on the same PCB so cache signals do not have to travel off the CPU, therefore diminishing signal degredation.

As already mentioned, they are more energy efficient, so I won't go into detail about that one