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AMD Dual-Core Performance Revealed
Timmus writes "In two separate articles, FiringSquad takes a look at the performance of AMD's dual-core Opteron CPU. The first article examines the performance of dual-core in scientific computing applications (MATLAB and LS-DYNA) as well as digital photography, while the second story focuses on the performance of dual-core Opteron paired against Intel's dual-core Pentium Extreme Edition in video encoding, Cinebench, and a few other applications. The performance improvements are pretty impressive in multi-threaded applications that take advantage of the technology."
Notice the lack of an Athlon 64 FX version of AMDs dual-core strategy. For the time being, its recognized that games are exclusively written for single-threaded operation and as such run better on single-threaded processors at elevated frequencies. Thus, the FX series marches on at 2.6GHz for now. ... so for games, keep to your single core CPU.
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Presumably the one major factor is cost of the motherboard.
Dual-cores can run on existing motherboards, with a bios update.
It cuts down the wait time of communication between the CPUs as the dual core chips don't need to travel on any sort of MOBO bus to communicate thus effectively giving a clock speed bus of inter CPU communication.
Less heat, less space, less energy requirements, eventually less money because there is only one chip.
article 1
article 2
With Opteron, you get extra HyperTransport interlinks without the extra pins that would be required.
With either architecture you get shorter wire runs, making timing easier to control.
...and for those who don't want to flip through pages and pages of flash banner ads:
Scientific Computing
MATLAB: Though the script includes a moderate amount of matrix math, it doesn't seem like much of it is parallelized. Our recommendation from two years ago still stands - for most Matlab users, the fastest performance will come with a single Athlon64 line.
LS-DYNA: I will bench the CPUs using two classic tests, a 3-vehicle collision and a single front-collision. The 3-vehicle collision takes more than 24 hours to complete - we do not have these numbers ready for this round of articles.
Digital Imaging
Capture One: With Capture One only supporting two CPU threads, the dual-core Opteron's lower clockspeed is a disadvantage.
Bibble: It took only 4 minutes to complete with the 2x Dual Core Opteron 275. 4 minutes! That's 4.2MB/sec of processing time - a 2x Dual-Core Opteron 275 can process RAW images about as fast as it takes to copy them from to your computer using a standard-grade USB 2.0 CF card reader!
Noise Ninja: On the slower Opteron 246, the fastest results were had with 4 threads, but on the faster CPUs, 8 threads was better.
Video
After Effects: Since the decoding of WMV-HD does not seem to take advantage of both CPUs, the performance gain from the Dual-Core AMD Opterons is virtually absent.
Probably the biggest advantage is that it's cheaper. (Although if by much, that remains to be seen.)
Plus, AMD's promise was something like being able to double the number of CPUs without having to buy a new motherboard. Though how much saving that will be (I expect AMD to price these pretty high), and whether it will mean that you're stuck with much slower cores to keep the TDP limits, that remains to be seen.
There are other possibilities for improvement, such as using a shared cache and IMC instead of just throwing two cores together and going over HT like on a dual CPU system. But AMD hasn't yet done that.
A polar bear is a cartesian bear after a coordinate transform.
http://www.anandtech.com/cpuchipsets/showdoc.aspx? i=2397
OK. Anyone have a quick simple explanation of why Dual Core over Dual CPU motherboard? are there inherent advantages to dual CPUs so close together?
Double your cpus without double the license fees, not to speak of the lower footprint.
Yes.
One example... dual core (true dual core) CPU have the ability to exchange data between the cores at faster rates and more importantly with less latency then when having to exchange data between CPUs on a dual CPU system. This can improve SMP flow.
Another example... good dual core implementations will utilize some form of cache unification to allow better bulk sharing of data between cores while still allow high-levels of independent cache activity (the IBM's Power5 is a good example of this).
1) Cost.
Since there need only be half as many sockets, the motherboard can be smaller, less complicated, and therefore less expensive. This is especially true in the case of single-socket motherboards, which are usually 50-60% as expensive as their dual-socket brethren. AMD has sweetened the cost savings even further by arranging it so that most single-socket motherboards already in use with a single-core CPU can accomodate a dual-core CPU after just a BIOS flash.
2) More efficient interconnection between the cores.
This advantage currently applies to AMD's design but not Intel's. As explained here, "As you can see, AMD didn't simply glue a pair of K8 cores together on a single piece of silicon. They've actually done some integration work at a very basic level, so that the two CPU cores can act together more effectively. Each of the K8 cores has its own, independent L2 cache onboard, but the two cores share a common system request queue. They also share a dual-channel DDR memory controller and a set of HyperTransport links to the outside world."
After reading the TechReport article I linked to above, it looks to me like AMD is way ahead in the dual core market in all of the areas that count: better backward-compatibility, better cache coherency, and lower heat.
Erlang.org: wow
On other benchmarks the AMD dual core gets 10-20% better performance! SiSoft Sandra is an exception, where there is a mixed bag between the two processors.
In the article on Anandtech, they do a pretty good job of explaining this.
Basically, in the past, programs that had multiple threads heavily favored Intel's Hyperthreading chips since they could handle multiple threads at once. AMD's chips lacked this capability. Intel's dual core chips did pick up a performance boost, but they didn't pick up the large boost that AMD's dual core chips did. AMD picked up such a large performance boost because their chips lacked hyperthreading, and now with two cores they're able to handle multiple threads at once whereas they couldn't before.
You are straight on. One of the major problems with large pipeline chips is that they fill the various cache slots with what is predicted to be needed. If you have a huge cache pipeline, and the CPU thinks its going to need certain commands in that pipeline, and it in fact doesn't, all those prefetched bits are wasted, and the CPU is suddenly memory bound for a huge number of cycles. On systems with tons of CPUs, this is a very large problem. If you have 32 CPUs, and 15 of them incorrectly predict which branch will be taken in a single cycle, suddenly all those CPUs are going to be choked.
The biggest advantage is it's the only way to get a faster processor. You won't see a 4GHz processor in production soon. It's a matter of physics. So instead, you'll wait for applications to better support parallel processing, and then get a dual-core CPU at that point.
Anandtech has an AMD dual core Opteron and Athlon64 X2 article that might compliment the original poster's story pretty well. It has a sh*tload of benchmarks:
? i=2397
http://www.anandtech.com/cpuchipsets/showdoc.aspx
I really wish they wouldn't do gaming benchmarks with an Opteron in stories like these. Just because the Opteron used has similar specs to the dekstop processor that hasn't been released doesn't necessarily mean that the gaming benchmarks are all that useful. Just my 2 cents.
It'll be interesting to see how soon prices fall for these AMD processors (server and desktop) when they go mainstream. Read the cost comparisons for these badboys in the article.
Finally, I'm glad that Anand decided to demonstrate that the new AMDs will be backwards compatible with Socket 939 motherboards WITH BIOS revisions. Intel's dual core processors don't offer that luxury, from what I read in the article.
IronChefMorimoto
"So what about the average user?"
Windows is multi-threaded and behaves better in a multi-processor environment. Even the average user will notice this.
"Derp de derp."
AMD ones appear to have the same Thermal Design Power (about 90W) as their single-core chips.
The reason Microsoft gets so much more scrutiny and leagle flack on the bundling issue is because they have been found (leagly) to be a monopoly. This changes the rules for them so as to prevent them from locking out any future competition or taking over related/inlinked markets by virtue of thier having a near captive audience.
Apple with it's small slice of the market is very unlikely to say put opera out of bussiness by shipping thier own browser for free with thier operating system like Microsoft did to Netscape(I know that's a simplification of ie/netscape history, but it serves to illistrate my point I hope).
In short Microsoft is a victim of thier own success here.
Mycroft
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It's not cheaper initially, that's for sure for AMD parts :( Check out AnandTech's review. Dual core Opterons cost 3.5X as much as single cores at the same speed. Dual core A64s are going to cost 2X as much as the single core speed equivalents. Intel's parts costs 1.5X as much (at the entry level) as the single core speed equivalents.