Affordable Dual Core from AMD: Athlon 64 X2 3800+
by Anand Lal Shimpi on August 1, 2005 9:36 AM EST- Posted in
- CPUs
For the past couple of months, we've asked, hoped and dreamed for it, and today, AMD is launching it - the $354 Athlon 64 X2 3800+; the first somewhat affordable dual core CPU from AMD.
If necessity is the mother of invention, then the birth of the Athlon 64 X2 3800+ should be no surprise to anyone. In one of their strongest CPU paper-launches ever, AMD put their best foot forward this past May and introduced the Athlon 64 X2 processor. While AMD was late to the desktop dual core game compared to Intel, the Athlon 64 X2 processor had absolutely no problem outperforming Intel's Pentium D. But at the end of the day, despite AMD's clear victory, our recommendations were quite complicated, thanks to one major flaw in AMD's execution: price.
The cheapest dual core Pentium D processor could be had for under $300, yet AMD's cheapest started at $537. Intel was effectively moving the market to dual core, while AMD was only catering to the wealthiest budgets.
The Pentium D 820, running at 2.8GHz and priced at $280, offered the most impressive value that we've seen in a processor in quite some time - if you could properly use the power. Multitaskers and users of multithreaded applications found themselves with the cheapest 2-way workstation processor that they had seen since the SMP Celerons and ABIT's BP6. While Intel satiated our demands for affordable dual core, we knew it wasn't the perfect option. AMD's Athlon 64 X2 was the better overall performer, just at the very wrong price point.
After much pressure from all sides and some very important manufacturing changes, AMD went ahead with the decision to release a cheaper Athlon 64 X2. The decision was made around the time of Computex 2005 and that's when we first heard of the $354 Athlon 64 X2 3800+.
The Athlon 64 X2 3800+ is basically two Athlon 64 3200+ cores stuck together, each running at 2.0GHz and each with its own 512KB L2 cache. This is a full 200MHz lower clock per core than the 4200+, but with the same amount of cache.
The original Athlon 64 X2 (Toledo core) processors all had the same exact specifications:
Update: As many of you have correctly pointed out, the 4200+ and 4600+ were available as both Toledo and Manchester cores. More than half of the Athlon 64 X2's transistor count is spent on cache, which means that if there are going to be any manufacturing defects on the chip, they will more than likely occur in the processor's cache. Born out of that fact, the Toledo based Athlon 64 X2 4600+ and 4200+ were nothing more than 4800/4400+ X2s with too many manufacturing defects; instead of throwing the bad cores away, AMD simply rebranded them and sold them at lower price points. The problem with this approach is that an Athlon 64 X2 4200+ took the same amount of space on a wafer as an Athlon 64 X2 4800+, despite only having half the cache. Thus we have the Manchester core: a core designed from the ground up to only feature a 512KB L2 cache per core.
As manufacturing ramps up, yields improve and it is now possible to actually create a cost-reduced Athlon 64 X2, using the smaller Manchester die - and that's where the Athlon 64 X2 3800+ gets its cost savings.
The transistor count of the 3800+ goes down to 154 million, and the die gets shrunk down to 147 mm2 compared to the 233.2M and 199 mm^2 of its bigger brothers (4800/4400+). The thermal envelope of the new core also dropped from 110W down to 89W, both still lower than Intel's Pentium D or single-core Pentium 4 for that matter.
With a smaller die and lower transistor count, the Athlon 64 X2 3800+ is able to support its $354 price tag.
If necessity is the mother of invention, then the birth of the Athlon 64 X2 3800+ should be no surprise to anyone. In one of their strongest CPU paper-launches ever, AMD put their best foot forward this past May and introduced the Athlon 64 X2 processor. While AMD was late to the desktop dual core game compared to Intel, the Athlon 64 X2 processor had absolutely no problem outperforming Intel's Pentium D. But at the end of the day, despite AMD's clear victory, our recommendations were quite complicated, thanks to one major flaw in AMD's execution: price.
The cheapest dual core Pentium D processor could be had for under $300, yet AMD's cheapest started at $537. Intel was effectively moving the market to dual core, while AMD was only catering to the wealthiest budgets.
The Pentium D 820, running at 2.8GHz and priced at $280, offered the most impressive value that we've seen in a processor in quite some time - if you could properly use the power. Multitaskers and users of multithreaded applications found themselves with the cheapest 2-way workstation processor that they had seen since the SMP Celerons and ABIT's BP6. While Intel satiated our demands for affordable dual core, we knew it wasn't the perfect option. AMD's Athlon 64 X2 was the better overall performer, just at the very wrong price point.
After much pressure from all sides and some very important manufacturing changes, AMD went ahead with the decision to release a cheaper Athlon 64 X2. The decision was made around the time of Computex 2005 and that's when we first heard of the $354 Athlon 64 X2 3800+.
The Athlon 64 X2 3800+ is basically two Athlon 64 3200+ cores stuck together, each running at 2.0GHz and each with its own 512KB L2 cache. This is a full 200MHz lower clock per core than the 4200+, but with the same amount of cache.
Note: The 512KB X2s are available in both 154M and 233M transistor versions.
A New Core
AMD didn't sit on the X2 3800+ just because they were greedy and expected everyone to gobble up the $500+ parts. Instead, today's release is the result of a slightly revised core, codenamed Manchester, specifically designed to cut costs.The original Athlon 64 X2 (Toledo core) processors all had the same exact specifications:
- 233.2M transistorsFor the Athlon 64 X2 4800+ and the 4400+, the shared transistor count and die size made sense. They both were identical from a transistor standpoint, one chip just ran 200MHz faster than the other. But the 4200+ and the 4600+ weren't identical; unlike the 4800/4400+ X2s, the 4200+ and 4600+ only had a 512KB L2 cache per core, not a 1MB L2.
- 199 mm2 die size
- 110W max power
Update: As many of you have correctly pointed out, the 4200+ and 4600+ were available as both Toledo and Manchester cores. More than half of the Athlon 64 X2's transistor count is spent on cache, which means that if there are going to be any manufacturing defects on the chip, they will more than likely occur in the processor's cache. Born out of that fact, the Toledo based Athlon 64 X2 4600+ and 4200+ were nothing more than 4800/4400+ X2s with too many manufacturing defects; instead of throwing the bad cores away, AMD simply rebranded them and sold them at lower price points. The problem with this approach is that an Athlon 64 X2 4200+ took the same amount of space on a wafer as an Athlon 64 X2 4800+, despite only having half the cache. Thus we have the Manchester core: a core designed from the ground up to only feature a 512KB L2 cache per core.
As manufacturing ramps up, yields improve and it is now possible to actually create a cost-reduced Athlon 64 X2, using the smaller Manchester die - and that's where the Athlon 64 X2 3800+ gets its cost savings.
The transistor count of the 3800+ goes down to 154 million, and the die gets shrunk down to 147 mm2 compared to the 233.2M and 199 mm^2 of its bigger brothers (4800/4400+). The thermal envelope of the new core also dropped from 110W down to 89W, both still lower than Intel's Pentium D or single-core Pentium 4 for that matter.
With a smaller die and lower transistor count, the Athlon 64 X2 3800+ is able to support its $354 price tag.
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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.