Multiple Cores?
AbsoluteZero
The new film by Quentin KoopantinoRegistered User regular
The new film by Quentin KoopantinoRegistered User regular
So I'm looking into getting a new computer or possibly building one. However, one thing I don't exactly understand is the benefits of a multi-core processor. For instance, what is the advantage of a dual core 2GHz processor vs. a single core 2GHz processor? Why should I shell out any extra cash for a multiple core machine?
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With this in mind, having multiple cores is like having multiple processors, only on the one single processor die instead of having multiple physical processors to install. This means that calls to the processor cache by each core is significantly faster, as they no longer need to traverse the system bus. With less distance to travel, the signals degrade less as well, so faster transfer rates to cache are possible.
Furthermore, SMP-aware applications can happily balance their threads between cores for simultaneous execution.
Of course, as with multiple physical CPUs, adding cores does not increase the clock speed. (If I have to read one more eBay auction claiming "dual core 2 Ghz = 4 Ghz!!!", I will kill the lot of them.) However, as multicore CPUs are becoming decidedly common, expect just about every new game to benefit as developers code for them. SMP stalwarts like Photoshop should also see a tasty speed increase.
I've found that even in situations where you wouldn't *think* it would help, your computer is rarely running only 1 application. For instance, you boot up your Windows PC, and within the first 2-4 minutes your antivirus loads up, your spyware monitor loads up, your Windows Update thing scans, etc. On a single-core/CPU computer, each of those ends up on the same chip, which is why a computer would be so slow when you hit the desktop for the first few minutes.
With a multicore/cpu computer, those processes essentially take half the time, and if you load up Firefox right away, it can hop on a core with low current usage and load that much more quickly.
With single-threaded applications, you likely won't see much difference by having multicore, within than single application. This is currently a big deal with high-end audio applications that run instruments and effects and are often single threaded. They end up maxing out the CPU they're on and running out of juice, without the user really noticing any problems (making it harder to diagnose). On the other hand, applications like that can use almost an entire core w/o other applications messing with them.
A friend of mine with a dual core often has one monitor happily playing a divx movie while he is doing whatever he wants on the other monitor with no effect on the movie playback. It is very slick.
I suspect I will be drooling once my wifes new MB, CPU, and ram arrive. But she has a lot more need for multitasking right now.
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Doesn't [email protected] have multi-core support? I could have sworn it did, but I could be wrong.
To the OP, while dual-core is definitely the way to go now, don't automatically assume that more cores will always be significantly better. It will depend entirely on what you are using the computer for, and the specific software running. For example, most modern games are only just beginning to truly take advantage of dual-core processors, while quad-core doesn't seem to offer much in the way of gaming performance benefits just yet.
Like everything else in new technology, there is always a price-to-performance sweet spot based on need, and it'd be a good idea to figure out what exactly that is for the kind of PC you want to own. Going too far ahead of the curve gets expensive fast.
Also, I hear the new ATI Radeon HD 3870 X2 has two GPUs. I don't know if they're dual core or just two GPUs on the same board, but this is still the first I've ever heard of such a thing. Anyone know if this would be worth checking out?
It's two GPUs on one board. It's nothing new, actually. Nvidia did something similar with the 79x0 GX2 (although those were really two 79x0 boards sandwiched on top of each other). Much earlier, ATI had the Rage Fury MAXX cards, which sported two Rage 128 GPUs. Let's not forgot the Voodoo 4/5 series, the top dog being the infamous Voodoo 5 6000 with four VSA-100s on one PCB, and required an external power source to juice it up. You thought video card technology is crazy today...
Well it's true from the standpoint that the Phenoms have four independent cores on the die while the Q's are two Core Duo's on a single die.
totally buy my video game InFlux on Steam or Humble Store or GOG or Amazon!
They're good for what they are, but they still lag behind Intel's Qs.
The architecture itself though has potential. Only time will tell.
What's the best quad core you can get right now? And also what's the second-best.
totally buy my video game InFlux on Steam or Humble Store or GOG or Amazon!
As for the Phenoms, I think the best bang for the buck is the 9500. As the next step only gives you an extra 100Mhz for $34.
So much a matter of taste though. Like I know the Intel/Nvidia combo's performing much better right now for not that much more but I have this bad taste in my mouth with them for whatever reason.
My single core Athlon 64 used to take about 4 days to rip 8 to 10 DVD into XviD files....
My Q6700 did the same project in 8 hours....
Brief history of multi-core technology....
AMD releases the Athlon 64x2 inot the market and says "Look we're first into the dual core processor market, look at how blazingly fast our processor are!"
Notice the cross bar and how it allows the two cores to communicate properly
Intel says "Oh shit, we need something to compete" and out pops the Pentium Ds, essentially two Pentium 4 duck taped together on a single chip....
The important thing to see here is the arrows between the two cores and the front side bus, this is essentially a 3 way stop, they cannot all talk to each other at the same time, so either the two cores can talk, or one core and the front side bus, or the other core and the bus, but not all three together. VERY inefficient design.
Intel's R&D department then had to act fast and came up with the Core 2 Duo design which mimicked AMDs efficient design...
In this picture the L2 cache is acting like AMDs crossbar, which allows for seemless discussion between the cores and the system bus, this allows both cores to access the same information within the cache and be far more efficient than the indepent cache system the x2's have...
Intel then decided "Well you know, we could duct tape two of thee together and be the first into the Quad Core market way before AMD and get ourselves known for it early...
Could not for the life of my find a better picture
AMD Meanwhile bought ATi to get at their chipsets so AMD could compete against Intel's own chipset design and stop worrying about selling their concepts to chipset manufacturers, instead AMD can now create their own chipsets and prove their optimum configurations. This move slowed them down a bit, but overall AMD has better footing against Intel now. AMD however said "Look, they did the same thing again, that tape doesn't fool anyone....
I know the picture represents a triple core, but it also applies to a quad core design...
Basically, we can see AMD learned from Intel's efficient design and added a shared cache level, Intel shared cache is higher so it allows for more number crunching, but AMDs power is in the cross bar which allows for the 4 cores to talk to the RAM and the rest of the system at the same time. If AMD were to increase the L3 cache, in theory the ssytems should pick up significantly more speed.....
Intel turned around and said "Look AMD our chips are still faster than, *sticks their tongues out*, neener neener neener neener...."
AMD of course is the brainiac in the corner who typically takes the abuse and just sits there plotting and planning their next triumph...
The way I see it Intel will do one of two things... They will A: Release their own variant of a true quad core processor so that they can later duct tape two of the together to achieve an octo-core processor or B: Release an Octo-Processor that is four Core 2s on the same die, while AMD will make a true octo-core processor.....
Also note that Intel's design allows them to increase the number of core on a processor fairly rapidly as they can just keep duct taping Core 2s together, but you then end up at a ceiling of performance as that damned bus will always cause a traffic jam and AMD hypertransport system will allow the spice to flow....
Edit: Hey, I was right.... http://www.digitimes.com/mobos/a20080201PD211.html
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Holy shit! Sony's new techno toy!
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Not nearly as insane as a six megabyte cache. Jesus.
That said, I'd like to see what kind of crazy shit you could pull using eight cores with 6MB of cache pumping data out to a couple of quad-core GPUs. Might even be able to play Crysis at better than 800x600.
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Unpossible!
But seriously though, I'm really excited to see what AMD and Intel both will bring to the table in the future. I have a Core 2 Duo right now because when I built this computer it was the best thing available at the time, and it's still a damned good processor. However I've always been a fan of AMD and I trust that they'll come out on top again and my next computer will feature one of their CPUs.
Also, my roommate with the Phenom is planning on getting 4 more gigs of RAM, and 3 more 3870's (once the drivers for all that comes out he says). Is this insane? (y/n)
Well, they're trying to do both.
The goal is still ultimately to make a faster processor, but since this is getting harder and harder to do, adding more processor cores adds that extra kick to make up for it.
Now if Intel and AMD somehow manage to create an architecture that are both processing speed breakthroughs and multi-core integration wonders, good times will be had by all right after that happens.
Time was, back in the bad old days of the WinTel pseudo-monopoly, that Microsoft could have just told Intel to redesign its chips, put out a completely new system architecture and everyone would have either loved it or died, computationally speaking of course.
Nowadays, only Apple has both the system architecture and the (proprietary) hardware stranglehold to switch over to an entirely new CPU architecture almost at will. In fact they already did it once...they just went in the wrong direction for the sake of cheapness.
Not that RISC lets you make faster chips in terms of clock rates, that's still a fairly hard limit of how much juice you can pump into a piezoelectric crystal; it's just that way back when BBC/Acorn was the third computing platform in the UK, they had a chip that was outperforming a P90, including when running Windows through an interpreter, that had a clock speed of 25 MHz. And, IIRC, it was out at retail before the P90 too. That is, you get way more bang for your buck...as almost every mobile phone manufacturer today will tell you.
[/rant]
tl;dr:
Current system bad because of BC. Scrap BC for new (oooold) way, go fasta.
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In fact, I'm pretty sure they've been doing that since the Pentium II.