aslanwcpu :
each core is about 3 GHz for both processors, does this mean that the quad core is twice as fast as the dual core processor?
The answer is no! This is the main misconception that people have about multi-core processors. You don't multiply the speed of one core by the number of cores to get the "total" speed of a multi-core processor. The two processors in this example actually perform at the same speed. The truth is, less than 1% of software on the market can utilize multiple cores, which means that most of your programs (probably all of them) can only run in one at a time. This means that the speed of your programs are fully dependent on the speed of a single core. You might be thinking "well, what if I'm running multiple programs at the same time?" The reality is, most programs can perform a task faster than you can switch to another program. The most notable exception to this rule is video editing software, which usually does utilize all of your cores.
Realistically, you will not notice a difference in speed between a system with a dual core processor and a system with a quad core processor, unless you are running video editing programs.
So what does all of this mean? Don't waste your money on a quad system unless you create and edit videos professionally, or run specialty software that can utilize all of your cores. You are much better off putting your money towards a dual processor or system with more GHz and a higher L2 cache.
Everyone agree with this???????????????????
Lets brake this down as there are some rights and wrongs.
each core is about 3 GHz for both processors, does this mean that the quad core is twice as fast as the dual core processor?
The answer is no! This is the main misconception that people have about multi-core processors. You don't multiply the speed of one core by the number of cores to get the "total" speed of a multi-core processor. The two processors in this example actually perform at the same speed.
You are correct on this. It's not like RAID 0 on storage drives nearing double speed. With cpu's, 3GHz x 4 core does not = 12GHz. Meaning if you run a single core program, it would be no faster on a quad core cpu with same speed and cache as dual core would.
The truth is, less than 1% of software on the market can utilize multiple cores, which means that most of your programs (probably all of them) can only run in one at a time. This means that the speed of your programs are fully dependent on the speed of a single core.
Well i dont know about you but there a lot more apps that are multi threaded than you really think and there other things to consider of why to chose 1 cpu over another in terms of cores than just the direct programing you're running.
While it's true that ton of programs still only use a single thread, 99% of programs on single core though is way to high. tons of stuff is multi threaded.
Todays Anti-virus, cad, 3d rendering, web browsers, games, scientific calculations, ect are all multi-threaded. I would guess 20 to 50% or more is multi-threaded these days and is increasing.
Now the better question is, How many programs can use 4 or more cores? Thats were the % drops dramatically to i would guess around 5 to 10%. Most programs that are multi-threads can only run 2 threads and majority only really needs 2 threads for now. Anti- virus is a good example as todays storage drives are not fast enough to fill the cpu to capacity on more cores.
Majority of games only run on 2. Although there starting to be able to use 4 and more cores. (ac2 and fsx are a good example).
Now you the other thing you also have to include is stuff like the drivers, what hardware you have/getting, and how powerful and/or many gpus you're have in a system. As that too will determine how many cores you need.
Example for a game:
Lets look at all but the core i7.
Intel Core 2 Quad Q9550 2.83 GHz, 12MB L2 cache
Intel Core 2 Duo E8400 3.0GHz, 6MB L2 cache
Intel Pentium E6300 2.8 GHz, 2MB L2 cache
As we see in this chart between these cpu's, most of the Nvidia gpus showed major increase in performance with this game when going to 4 cores from 2 and it's only a dual core game that im aware of.
Whats going on with Nvidia (at the time these charts were made) most powerful graphic cards? Some might say it's the amount of l2 cache between the core 2 quad and core 2 duo.
Although if that was the case, wouldn't there be a much more performance increase going from a 2.8GHz, 2MB L2 cache Pentium dual core to Core 2 duo at 3GHz and with 3x the cache?
As going from pentium to core 2 duo only made the GTX 285 increase the average FPS by 7. While going from duo to quad increased it by 10 FPS. The only 2 thing the quad has going for it is the x2 amount of cache compared to the core 2 duo and 2 extra cores. The quad is slower GHz so thats not an advantage.
It's the drivers and gpu needing an extra core to run at it's full potential. So it's really depends on what you're doing.
You might be thinking "well, what if I'm running multiple programs at the same time?" The reality is, most programs can perform a task faster than you can switch to another program. The most notable exception to this rule is video editing software, which usually does utilize all of your cores.
Realistically, you will not notice a difference in speed between a system with a dual core processor and a system with a quad core processor, unless you are running video editing programs.
Hmm.... when most people mean multi tasking, they normally mean doing 2 or more task at once. There not switching around between different task. Like doing Anti-virus scanning and playing youtube or playing a game while Folding@home with single core client, running at the same time. (which i happen to be running F@H SMP client and typing on here at the same time. :lol: )
So you can utilize some to all you're cores with many single or dual core programs. Heck before Folding@home had an SMP client, for anyone that wanted to put all the cpu cores to work, they would run multiple single core clients up to the number of cores they had which would also count as multi tasking.
So what does all of this mean? Don't waste your money on a quad system unless you create and edit videos professionally, or run specialty software that can utilize all of your cores. You are much better off putting your money towards a dual processor or system with more GHz and a higher L2 cache.
Well, more GHz and cache doesn't always mean faster system unless you're talking about 2 cpu's in the same family.
I can take 2 quad cores without Hyperthreading, core i5 750 (2.66GHz. With each core have 256 KiB of L2 cache, and 8 MB of shared L3 Cache) and compare it to Core 2 quad q9650 (3.00GHz, 12MB of shared L2 cache) and the Core i5 wins even though it has lower GHz and cache.
Reason for that is the IPC (instruction per clock) on the core i5 is shorter than core 2 quad. Meaning it can get more work done clock per clock than the Core 2 quad.
If you we meaning of the came family of cpu's, than that hold hold true if you cant use 4 or more cores.
If you were wondering why i didn't include the core i7 in the chart above in the comparison that the reason why is Different micro architecture, Different IPC, ect would made it an unequal comparison. The 3 cpu's i compared are all the same arch which meant that they all have the same ipc.
Now as for wasting you money on quads, Well depending on who you chose and what you're using it for, maybe better to have a quad than a dual core for the price. (athlon ii x4's for only $90 to $100
)
Everyone agree with this???????????????????
Well from my length response, some things i can say i agree with and others not.
It's just much more complex than the programs you use. Hardware setup, multi tasking, drivers, all make this very hard to say "yes all you need is a fast dual core" for each person.
Also, Welcome to the Forums.
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