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This is not all that surprising...
By Motoman on 1/17/2009 12:52:18 PM , Rating: -1
...Intel and AMD shifting to multi-core CPUs as a way to make "better" products is problematic in a couple ways. First, as noted here, you have to deal with too many cores trying to access the same memory - I guess in theory (and I'm not an EE guy, so largely just speculating here), that you could put a dedicated set of RAM slots for each core on a motherboard...but with an 8-core machine you'd have a 3-foot square motherboard. So that's not going to work...

...the other problem is that the vast majority of what most programs do is fundamentally, and inalterably, linear...which is to say, it can't be split up and run across multiple CPUs/cores. To some degree, some programs (like games) can use multiple cores - you can send basic logic to one core, and physics to another, for example. Say you can come up with 4 fundamental threads within the program, so you can leverage 4 cores.

Then you are presented with an 8-core system. Looking at each of your 4 threads from before, you realize they can't be split any further...physics processing, for example, is exceedingly need the output from the last calc as input to the current calc, which then feeds the next calc, all in series - can't be performed in parallel. So there's no value in the next 4 cores.

Granted, I'm targeting desktop computers. Sure, we can get Oracle and SAP to run across multiple cores, but those are completely different types of applications. From a desktop standpoint, I honestly think that (barring some new magic I can't concieve of), 4 cores is likely to be the maximum that anyone is ever going to get any benefit from. And in all likelihood, 2 cores at X speed (2X total) will be essentially as fast as 4 cores at X speed (4X total) for the majority of applications, probably forever.

I think multicore CPUs are cool just for the sake of the technology. I just think that we are losing the plot in some regards...we need to make the applications we use faster, not just build a 32-core CPU simply because we can.

RE: This is not all that surprising...
By PrinceGaz on 1/17/2009 3:21:53 PM , Rating: 5

Actually physics processing isn't like that at all... it almost always consists of doing similar calculations on a large amount of data, and they can all be done in parallel. That's why things like PhysX can be handled so much better by a modern GPU than on any x86 CPU.

RE: This is not all that surprising...
By Motoman on 1/17/09, Rating: 0
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See this link :

The multimedia class service is useless tho in my opinion.

As is readyboost useless.


RE: This is not all that surprising...
By Reclaimer77 on 1/17/2009 8:11:21 PM , Rating: 3
There is NOTHING surprising here. Sandia must enjoy wasting their time.

This is really no big deal. Intel and AMD have already dealt with this in the real world.

Nice job Sandia. I await your next breakthrough when you inform us of something else equally obvious and meaningless.

RE: This is not all that surprising...
By Motoman on 1/18/2009 11:09:22 AM , Rating: 2

Really? Please illucidate this topic for us.

RE: This is not all that surprising...
By Reclaimer77 on 1/18/2009 11:54:53 AM , Rating: 1
It's a non topic. You think Intel and AMD are a bunch of idiots who blindly add cores to CPU's without taking memory usage into account ?

I'm not sure what you want me to say. The article is simply stating the obvious, and it sure as hell isn't news to Intel or AMD. Why do you think we have on die memory controllers and dual and triple channel memory now ?

How do you explain that software WRITTEN for 8 threads runs faster in the i7 than quad cores ?

RE: This is not all that surprising...
By Motoman on 1/18/2009 12:08:10 PM , Rating: 2
...How do you explain that we can expect *all* applications to benefit from an 8-core processor? Or 16-core?

I think that Intel and AMD are geniuses...they ran into a wall and found a way around it. But I think people like you are either far too into specialized niches that *will* benefit from lots of cores, or too far bought into the marketing to actually think about the ramifications for the typical consumer.

Applications and games that are used by the typical consumer are simply not going to be able to spread across a whole lot of parallel cores. They just aren't. So if there is some magic that will allow purely serial processes to run across multiple parallel cores, please let me know. If there isn't, please stop apparently pretending that more cores is better for everything...because it isn't.

By retrospooty on 1/19/2009 8:49:05 AM , Rating: 2

??? I dont... Because we dont. Who expects that?

What we ALL know is that only mutithreaded apps benefit from multi cores and we ALL know that most games and high end apps that need extra CPU power ARE being written for multiple threads. Apps that dont need the CPU power are generally left alone.

By Jeff7181 on 1/18/2009 1:57:12 PM , Rating: 3
Ever heard of double data rate memory? Dual memory channels? Quad memory channels? Quad pumped busses?

CPU manufacturers understood a ALONG time ago that as the processing power of CPU's increase, the demands on the external bus increase also. All those things mentioned above are designed to provide the CPU with more memory bandwidth to allow the CPU to operate to it's potential.

Do you think Intel is using three memory channels for their newest chips because they got sick of seeing either 2 or 4 memory slots on a motherboard and wanted to mix it up a little with 3 or 6? Of course not... it's because they've already identified a problem feeding their new dual and quad core processors with enough data for them to crunch so they increased the memory bandwidth by adding a third channel.

By fri2219 on 1/18/2009 10:01:54 PM , Rating: 2
No kidding, welcome to 1988.

By retrospooty on 1/19/2009 8:46:16 AM , Rating: 2
"This is really no big deal. Intel and AMD have already dealt with this in the real world."

Yup... I dont know if I blame sandia for saying it though... Kind of not worth posting on this site though. Considering Sandia is a huge govt. funded science lab and this is a consumer site...

By SmartWarthog on 1/19/2009 12:36:15 PM , Rating: 2

The Phenom's split DRAM controller probably accounts for much of its performance improvements over its predecessor.

RE: This is not all that surprising...
By Oregonian2 on 1/19/2009 3:14:59 PM , Rating: 2
You've had your posting's point score knocked down a few because your posting, although I think written with good honest intention also showed a rather large, uh, lack of knowledge of processor architecture and usage. I personally think your ideas should be argued against instead, but that's me. And yes, I am an "EE Guy" who professionally designed computer systems starting with the Intel 8008 back when it was hot stuff. In terms of this thread, hunt down photos of CPU die -- there usually are some when new processors come out. Note how the "CPU proper" usually takes only a minority portion of the chip! Most of the area is usually taken up by cache memory. Think about the implications of that observation in the context of this thread.

By William Gaatjes on 1/19/2009 3:34:22 PM , Rating: 2
For the interested :

and to top it off with some tests :

Why is cache so important ?
Well, triple 3 channel memory is around 16 times slower then the cache of Intels fastest offering i7 965. Imagine that the execution unit's inside the core i7 965 would be just waiting for data wihtout cache. the cpu's would be terribly slow. And the x86 complete(thus meaning including decoders load and store ) execution unit's are still big when compared to other modern architectures. But they only need to be because they need to decode the variable lenght x86 instruction set (meaning instructions can be for example 8 bits or 16 bits or 32 bits or 64 bits long ) This makes it less easy to feed the instructions as easy digestive food to the execution unit's.


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