Affordable Dual Core from AMD: Athlon 64 X2 3800+
by Anand Lal Shimpi on August 1, 2005 9:36 AM EST- Posted in
- CPUs
AMD's Efficiency Advantage?
Before we get to the actual barrage of performance tests, there is one issue that we have been wanting to tackle for quite some time now.AMD has often argued that their dual core architecture is inherently more efficient than Intel's, primarily because of their System Request Queue (SRQ). All core-to-core transfers occur via this queue instead of over a main, shared FSB, which is the case in the Pentium D.
Johan put AMD's architecture to the test by measuring the latency of cache-to-cache transfers in AMD's dual core chips vs. Intel's. The results were quite impressively in favor of AMD's architecture. Cache-to-cache transfers on Intel's dual core CPUs took over twice as long as on AMD's dual core CPUs, but at that time, we could not find any real world benefit to the architecture.
Armed with a bit more time, we went through all of our benchmarks and specifically focused on those that received the most performance gain from dual core architectures. Using these multithreaded and/or multitasking benchmarks, we looked at the performance improvements that the dual core processors offered over their single core counterparts. For AMD, making this comparison was easy; we took the Athlon 64 X2 3800+ and compared it to its single core equivalent, the Athlon 64 3200+. For Intel, the comparison is a bit more complicated. The inclusion of Hyper Threading makes the single-core to dual-core jump a little less impressive in some cases, thanks to the fact that virtually all single-core Pentium 4 processors these days can execute two threads simultaneously. Thus, for Intel, we had to look at HT enabled, dual core and dual core with HT enabled, all compared to single core performance to get a complete picture of Intel's multithreaded performance scaling.
Remember that all performance increases are with reference to a single core processor, and in the case of Intel, we are talking about a single core Pentium 4 with HT disabled. More specifically, we used a Pentium D 830 (3.0GHz) for the dual core tests and compared it to its single core counterpart - the Pentium 4 530 (3.0GHz).
First, we have our Winstone 2004 benchmark suite; we omitted Business Winstone 2004, since it shows virtually no performance boost from dual core CPUs and instead, focused on Multimedia Content Creation Winstone 2004 and the Multitasking Winstone tests.
It is also worth noting that although Hyper Threading improves performance with a single core, enabling HT on the dual core CPU actually yields lower overall performance than if we had left it off (+24.1% vs. +39.1%). Johan explained exactly why situations like this exist on the Pentium D in his "Quest for More Processing Power".
Next up is the SYSMark 2004 suite. In all but two of the tests, AMD scales slightly better than Intel when going to dual core. The scaling advantages aren't huge, but they are tangible in some of the tests.
Once again, while Hyper Threading itself tends to impress, HT + dual core gives us a mixed bag of results, sometimes outperforming dual core alone while falling behind other times.
Finally, we have our application-specific benchmarks; here, we have AMD scaling better than Intel in 3 out of the 5 tests, but then in the remaining 2, Intel scales better.
While the Athlon 64 X2 does have much better cache-to-cache transfer latencies than the Pentium D, it appears as if for the most part, those advantages don't surface in real-world desktop usage. That being the case, the Athlon 64 X2 3800+ must outperform the Pentium D 830 based on the performance advantages of its individual cores in order to win this battle, not based on any dual core architectural efficiencies. So, does it?
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gibhunter - Monday, August 1, 2005 - link
Whatever, point of entry into dual core is $250. Like it or not, if someone wants it for what I said, than the cheapest way to get there is with an Intel chipset with built-in graphics and the P4 D820. For my personal computer I'd go with the AMD, but for a cheap PC that will be good for everything but gaming, the Intel solution is the way to go.Ps. The D820 is not as hot as you make it out to be.
krisia - Monday, August 1, 2005 - link
Uh, funny, My Intel D820 runs the same games I was running on my AMD 3500 and I can't tell any difference.And, no the 945 mobos and DDR2 memory aren't any higher in price if you look...
I voted with my $$$. :)
SDA - Monday, August 1, 2005 - link
Just because you can't tell the difference doesn't mean that one doesn't exist. This is stock advice. And anyway, this isn't about whether or not you're happy with your purchase decision, it's about whether that purchase decision is a genuinely good choice. Bose speaker buyers are generally happy with their purchases, but that doesn't mean Bose speakers are any good.krisia - Tuesday, August 2, 2005 - link
Well, I have my systems OC'd, the D820 by 10% and my ADM 64 3500 by 20% and ran x2demo. Both systems running Geforce 6600GT. Came out virtually the same frame rates. As I paid less $$$ for my D820, yes I'm happy with it for what I do... Any other analogies that might help?SDA - Tuesday, August 2, 2005 - link
I never said it was a bad choice, krisia, only that you can't extrapolate from your own very limited experience and tests and say that it must be a better choice in general. I'm sure that you made the perfect choice for your situation, but that doesn't mean it's the right choice for everyone/anyone/someone else.Again, the Bose analogy. A Bose buyer might put their favorite CD in their Bose system and decide that it sounds just fine compared to their neighbor's stereo. They made a fine choice for them, but that doesn't mean it's a choice they should recommend to others. Ever.
Any other analogies that might help? ;)
SDA - Monday, August 1, 2005 - link
Use the reply button to reply to comments. ;)Actually, I would say that I have a fairly accurate idea of how hot the 820 and 830 run. The 820 is quite possible-- easy, even, to cool (how could it not be), but the fact of the matter is that it is nearly impossible to get a silent air-cooled system with one, and it is quite difficult to get one that's merely quiet instead of "noise-reduced." If you beg to differ, you'd be arguing with an SPL meter, meaning that you have probably been deafened already.
Also, "whatever" is not an adequate response to "Intel dual core motherboards make up most of the cost difference." Try again.
gibhunter - Monday, August 1, 2005 - link
Repeat after me: NOT CHEAP ENOUGH!!!I do not care that it's faster than Intel's dual core cpu. Intel's CPU is $100 cheaper. If I'm building a new PC for web, office and occasional DVD encode, I'm buying the Intel chip. Plain and simple, the $100 sure as hell makes a difference. No enthusiasts will go for the 3800+ unless he is willing to OC the hell out of it. Your regular guy that just wants a good, stable PC with adequate power to do anything and dual core to be able to encode video and happily keep on making his powerpoint presentation, the Intel chip will aloow him to do so and save a hundred bucks in the process.
Whatever, AMD is obviously not listening.
Zebo - Monday, August 1, 2005 - link
AMD's cost much more to make because they must have perfection over two cores on a single die vs. intel who slaps two prescotts together. You pay a performance price for Intels way of doing things which is reflected in the lower price.Too bad you're only looking at CPU price.. when you consider power, mobo, and ram the pentium dually setup costs more money.
fitten - Thursday, August 4, 2005 - link
AMD's cost much more to make because they must have perfection over two cores on a single die vs. intel who slaps two prescotts together.What are you smoking? The AMD X2s are a single chip. The Intel parts are also a single chip. Intel does not "slap" two Prescotts together to make the dual core parts. They are two cores on a contiguous piece of silicon just like the AMD parts are. Now, you can talk about Intel's implementation of dual core logic not being as good as AMD's and the like, but please quit with the myth that Intel's dual core chips are actually MCMs because they aren't.
kmmatney - Monday, August 1, 2005 - link
From what I can see, Intel 955 chipset motherboards are around $180 - $220, which is a lot more expensive than a decent Socket 939 motherboard. SO overall thge system cost is much cheaper than the Intel 830, and very close to the 820.