Affordable Dual Core from AMD: Athlon 64 X2 3800+
by Anand Lal Shimpi on August 1, 2005 9:36 AM EST- Posted in
- CPUs
Power Comparison: Manchester vs. Toledo
In our first review of the Athlon 64 X2, we were astounded by the fact that the fastest Athlon 64 X2, thanks to its cool running 90nm process, consumed less power than any single core Pentium 4 processor, not to mention all of the dual core models.We also noted that a dual core Athlon 64 X2 processor used less power than a single core 130nm Athlon 64, once again a testament to AMD's transition to 90nm.
This time around, we're interested in the power consumption benefits of the new Manchester core. AMD says the core drops the maximum power consumption from 110W down to 89W, but what is that in the real world?
In order to find out, we performed one simple test; we clocked an Athlon 64 X2 4200+ based on the old Toledo core at 2.0GHz, the same clock speed as the X2 3800+, and measured the total power consumption of the system. We then swapped out the Toledo based X2 for a new Manchester based X2 to see, clock for clock, what the tangible decrease in power consumption was.
Remember, we're only looking at total system power consumption - obviously CPU power consumption will be a lot lower, but with identical system specifications, the CPU's impact on power consumption should be the major variable that we're measuring here.
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dougSF30 - Monday, August 1, 2005 - link
2.0 and 2.2 GHz parts with 512K L2 x 2 = 89W, whether "BV" (Manchester) OR "CD" (Toledo).2.2 GHz 1MB L2 x 2 and 2.4GHz 512K or 1MB L2 x 2 = 110W, whether "BV" (Manchester) OR "CD" (Toledo).
Once again, http://www.amdcompare.com/us-en/desktop/Default.as...">http://www.amdcompare.com/us-en/desktop/Default.as...
is useful. Select the X2 line.
yacoub - Monday, August 1, 2005 - link
p5:The Roxio VideoWave test in PCWorld’s WorldBench 5 suite completes 6 seconds quicker on the Pentium D 830 than it does on the Athlon 64 X2 3800+.
yacoub - Monday, August 1, 2005 - link
"In one of their strongest CPU paper-launches ever"HAHAHAHAH :)
dougSF30 - Monday, August 1, 2005 - link
"Strongest paper launches ever" ??? Face it, you guys blew it in your original X2 article, claiming there would be no retail availability until late this year. Turned out that in June anyone who wanted one could buy one from Newegg or Monarch.BTW, the 4200+ and 4600+ were Manchester (OPN core code: "BV", Rev E4) cores (147mm^2) when launched. Now there are also Toledo (OPN core code: "CD", Rev E6) versions, but they did not show up until recently.
Check the Desktop Processor Quick Reference Guide (and OPNs of parts sold since June from various vendors-- the 4200 and 4600 were "BV" Manchester parts):
http://www.amdcompare.com/us-en/desktop/">http://www.amdcompare.com/us-en/desktop/
(Select the X2 line)
masher - Monday, August 1, 2005 - link
Why no details on the testbed for each platform, specifically memory speeds used? It makes me wonder if the comparison used pricey low-latency ram for the X2 and bargain-barrel chips for the Pentium D..Also the article states "While AMD scales slightly worse than Intelin the MMCC Winstone and Multitasking 1 tests, AMD scales a lot better in the last two tests...". In one of those tests, AMD's "slightly worse" is 5.7%...whereas AMDS "a lot better" result on one of the other two was a measly 2.9%.
A 5.7% drop is "slightly worse", but a 2.9% increase is "a lot better"? What's funny is this obvious distortion was likely done subconsciously by the author, in his desire to boost his favorite.
When are you fanboys going to learn that processors are TOOLS. Use the best one for the job at the time...don't fall in love with them. If you were plumbers, you'd probably be masterbating each night with your pipe wrenches.
Houdani - Monday, August 1, 2005 - link
Eh? Where did you find the 5.7 and 2.9 numbers? Did the tables change since this comment was posted?For the numbers in question (table 1 on page 4) I'd rate the processors...
MMCC Winstone -- no advantage
Multitask 1 ---- Intel advantage (modest win) (+9.1%)
Multitask 2 ---- no advantage
Multitask 3 ---- AMD advantage (big win) (+29.3%)
Remove the MMCC and Multi_2 benches, and the comments are quite appropriate. Intel scales slightly better in Multi_1, while AMD scales a lot better in Multi_3.
justly - Monday, August 1, 2005 - link
I found (at least) some of the conclusions about “AMD's Efficiency Advantage?” bogus.The biggest error (and most obvious) is in the Winstone multitasking test 1, where the author commented that AMD is “significantly worse in the Multitasking 1 test”.
In that test duel core had no benefit because a single core AMD processor can handle that test without the need for a duel core. Looking at the actual numbers for that test on the “Multitasking Performance” page not only shows that the faster clocked single core AMD scale almost perfectly (based on clock speed) against its slower clocked duel core counterpart but it has the top performance in that test. Without looking at both the actual score and the percent of increase what is being proven has nothing to do with the “efficiency” of a duel core, but more to the point it shows how “inefficient” a single core is in that test. The 0% increase by moving from single core AMD to duel core AMD only goes to show how “efficient” the single core AMD is in that test scenario.
masher - Monday, August 1, 2005 - link
Aside from being near-intellible, this reply is far off the mark. No matter how efficient a single processor is, one expects two processors to be somewhat faster tha one. If this wasn't true, what would be the point of "duel-core" [sic] processors in the first place?There is no magic "100% efficiency" level for single a processor that cannot be exceeded. Even if there were, that efficiency would translate to the second core, making it faster as well. Two should be faster than one.
The efficiency being measured is not of the core itself, but of the scalability of multiple cores vs. a single one. In this particular case, there is a "100% efficient" standard-- linear scaling. If two cores run a benchmark twice as fast as one, then the dual-core implementation is 100% efficient...regardless of how efficient or ineffecient the actual cores themselves are.
Read the above carefully and consider it. It's not difficult to understand.
justly - Tuesday, August 2, 2005 - link
You can expect two processors to be faster than one, but that isn’t always true.What you failed to understand is the single core AMD processor is not limited by processing power in the Winstone multitasking test 1, so by adding the second core there is basically nothing for the second core to do, hence no performance increase.
Because of this it is inappropriate for the auther to gauge scalability for this test in a negative context as he did when he said “significantly worse”. In fact the worse a single core processor performs the more likely it will see a higher scaling when a second core is added because there is more work for the second core to process.
masher - Tuesday, August 2, 2005 - link
> "You can expect two processors to be faster than one, but that isn’t always true..."Of course it isn't. That's the purpose of this test...to determine the performance increase, if any.
> "...The single core AMD processor is not limited by processing power in the Winstone multitasking test 1, so by adding
> the second core there is basically nothing for the second core to do, hence no performance increase."
Oops, wrong again. You should have realized this simply from the fact that a higher clocked single-core A64 runs the benchmark faster. Claiming this test isn't even slightly CPU-bound and thus the poor result "isn't AMD's fault" is nonsense.
> "...the worse a single core processor performs the more likely it will see a higher scaling when a second core is added..."
Only for tests that are disk or memory-bound. And given the current differences in memory subsystems between AMD and Intel and the highly-integrated nature of AMD's memory controller, the "efficiency" of AMD's dual-core implementation is pretty much indistinguishable from the efficiency of their memory system.
So that just leaves highly disk-bound tests...which these tests were not. Even if they were, the results would still be valid. After all, if a single-core A64 runs as fast as possible due to disk constraints, then why should anyone spend more money on a dual-core chip?
Of course, one core of an X2 3800 is not nearly so fast as to run any of these benchmarks "as fast as theoretically possible". If multiple cores don't score higher, then its indicative of an underlying scaling issue, either with the chip or the test itself. Any other conclusion is nothing more than apologism and wishful thinking.