AMD Socket-AM2: Same Performance, Faster Memory, Lower Power
by Anand Lal Shimpi on May 23, 2006 12:14 PM EST- Posted in
- CPUs
AM2 in Detail
Of course the most prominent feature of AMD's Socket-AM2 platform is the new socket and its support for DDR2 memory. As we've already mentioned, Socket-AM2 is a 940-pin socket that is keyed differently from the original 940-pin Athlon 64/Opteron sockets; only AM2 processors will physically fit into an AM2 motherboard.
Socket-939 (left) vs. Socket-AM2 (right)
Socket-939 |
Socket-AM2 |
 |
 |
One of the Athlon 64's strongest selling points continues to be its on-die memory controller, which has of course been significantly changed for the new Socket-AM2 platform. All AM2 CPUs feature a 128-bit wide DDR2 memory controller, compared to the 128-bit DDR memory controller that we've come to know from the Socket-939 platform. A DDR2 memory interface actually requires more pins than a DDR1 interface, but AMD was able to keep the AM2 pin count down by removing a large number of unnecessary pins on the Athlon 64's package. When the Socket-940/939 Athlon 64s were first designed, approximately 10% of their pins were redundant and could be removed in later designs. Not desiring to introduce a new socket as frequently as its competition had, AMD waited until Socket-AM2 to remove those unnecessary pins thus enabling a dual-channel DDR2 interface in virtually the same pin count as the earlier DDR1 equipped CPUs.
All of the Socket-AM2 CPUs support up to DDR2-667, but the AM2 Athlon 64 X2 and Athlon 64 FX models support up to DDR2-800. Since Socket-AM2 unifies AMD's desktop socket strategy, all Semprons, Athlon 64s, X2s and FX processors will feature this dual channel DDR2 memory controller.
Corsair partnered with AMD and NVIDIA for the Socket-AM2 and nForce 500 review kits
The lineup of Socket-AM2 processors being introduced today are in the table below:
| CPU | Clock Speed | L2 Cache Size | TDP | Price |
| AMD Athlon 64 FX-62 | 2.8GHz | 1MBx2 | 125W | $1031 |
| AMD Athlon 64 X2 5000+ | 2.6GHz | 512KBx2 | 89W | $696 |
| AMD Athlon 64 X2 4800+ | 2.4GHz | 1MBx2 | 89W | $645 |
| AMD Athlon 64 X2 4600+ | 2.4GHz | 512KBx2 | 89W | $558 |
| AMD Athlon 64 X2 4400+ | 2.2GHz | 1MBx2 | 89W | $470 |
| AMD Athlon 64 X2 4200+ | 2.2GHz | 512KBx2 | 89W | $365 |
| AMD Athlon 64 X2 4000+ | 2.0GHz | 1MBx2 | 89W | $328 |
| AMD Athlon 64 X2 3800+ | 2.0GHz | 512KBx2 | 89W | $303 |
| AMD Athlon 64 3800+ | 2.4GHz | 512KB | 62W | $290 |
| AMD Athlon 64 3500+ | 2.2GHz | 512KB | 62W | $189 |
| AMD Sempron 3600+ | 2.0GHz | 256KB | 62W | $123 |
| AMD Sempron 3500+ | 2.0GHz | 128KB | 62W | $109 |
| AMD Sempron 3400+ | 1.8GHz | 256KB | 62W | $97 |
| AMD Sempron 3200+ | 1.8GHz | 128KB | 62W | $87 |
| AMD Sempron 3000+ | 1.6GHz | 256KB | 62W | $77 |
There's basically no price premium for the new Socket-AM2 chips, encouraging a quick transition to AMD's new DDR2 platform.
You will also notice that none of the model numbers have changed, so an Athlon 64 X2 4800+ on Socket-AM2 has the same clock speed and L2 cache size as the Socket-939 version. Since AMD's model numbers haven't changed, you already know not to expect any major changes in performance with Socket-AM2. In fact, the only difference on the CPU side is the introduction of the new Athlon 64 FX-62, Athlon 64 X2 5000+ and Athlon 64 X2 4000+.
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jmke - Wednesday, May 24, 2006 - link
here ya gohttp://www.digit-life.com/articles2/mainboard/ddr2...">http://www.digit-life.com/articles2/mainboard/ddr2...
Xenoid - Tuesday, May 23, 2006 - link
Ok so AM2 is AMD's offering for 2/4 06.The article title mentions same performance, faster memory, lower power. Wouldn't faster memory (in this case, ddr2) net a higher performance than what we're seeing here? Why is AMD bothering with DDR2 if it's not a significant improvement? If the power usage is so low, does this mean we can overclock a lot easier? I never understood the huge deal behind power usage on a cpu.
coldpower27 - Wednesday, May 24, 2006 - link
DDR production is slowing down, and DDR2 is continuing to mature, AMD does need to change to this memory type now, regardless if they like it or not.DDR2 also allows higher capacities, so you can probably reach 4x2Gb now as 2Gb modles are actually available on DDR2.
Considering DDR2 biggest advanatge bandwidth, is what AMD doesn't really need more fo right now, performance improvements will be negligible.
Furen - Wednesday, May 24, 2006 - link
Also, having all that extra bandwidth available allows AMD to throw quad-core on the same socket without much problem (maybe 1H07... whatever everyone says I doubt AMD will let Intel have the quad-core advantage for a year, I'd say we'll see very low volume quad-cores as close to Intel's Kentsfield/Cloverton as humanly possible). I know we've heard that AM3 is coming next year (from, who else?, The Inquirer) but considering that the DDR3 spec is not finalized quite yet and just how slowly AMD jumped into the DDR2 bandwagon I'd say we won't see it until 2008 at the earliest.Axloth - Wednesday, May 24, 2006 - link
I think there is also marketing side. There are lots of people "unaware" of ddr1-ddr2 comparison. And they probably think that ddr2 "must" be better than ddr1 because of that that "2". Like: ddr2 is upgrade or next generation of ddr1 so its gotta be much faster. Also, they might go for intel because intel uses ddr2 and amd only ddr1... And they think intel's better thanks to ddr2, disregarding cpu qualities of both amd and intel.pzkfwg - Tuesday, May 23, 2006 - link
If DDR2-800 barely beats DDR-400, I was wondering if the AM2 socket could actually be slower than 939 DDR-400 when using DDR2-667 !?! Knowing that a very large amount of people would buy cheaper AM2 system with DDR2-667, that would be ridiculous!mino - Wednesday, May 24, 2006 - link
YES and NO.Remember most people buy generic CL3 or CL2.5 DDR400. IMHO generic DDR2-666 should be ona par with that.
soydios - Tuesday, May 23, 2006 - link
So, the X2 4200+ will not run the memory at full speed. How safe would it be to overclock from 200x11=2200MHz DDR2-733 (2200/6=366x2=733) to 219x11=2200MHz DDR2-803 (2409/6=401.5x2=803) using OCZ DDR2-800 RAM and an Asus Xpress3200 motherboard?Furen - Wednesday, May 24, 2006 - link
I'd say that you can very likely get away with that overclock with pretty much every 4200+ as long as the motherboard allows you to do it.mino - Wednesday, May 24, 2006 - link
Safe as safe. At least from the point it won't blow up :)As for stability it all depends on the motherboard.