AMD Socket AM3 Arrives – The Real Phenom II

AMD has once again released a new CPU, but this is using the same name as previous yet still fairly new CPU.

One month ago to the day, AMD released what it likes to call the Phenom II processor. While it is an update upon the original Phenom architecture, it still uses the same AM2+ board architecture. For that reason it may be prudent to call it a Phenom II, but what does this mean for a new CPU that supports a whole new processor socket?-


AMD’s new addition to its Phenom II family just one month after the initial introduction of the Phenom II processor is the AM3 based system. Today we have been sent two new processors which are AM3 compatible; the Phenom II 810 and the Phenom II 720BE.

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However, we’ve a bit of sad news that needs to be mentioned before pushing onward. While we originally intended for this preview to be a full glimpse into the AM3 platform architecture and its performance characteristics with our complete benchmarking suite lined up, unfortunately due to some technical difficulties we fried our DDR2 memory before beginning our tests and didn’t have a DDR3 based AM3 board on hand to continue.

we will also be doing a comparison article between Phenom II using DDR2 and DDR3 very shortly, so you will be able to make your choice on what will be the best setup for you.

The New Phenom II

AMD unveiled several new Socket AM3 processors, including the Phenom II X3 720 Black Edition (2.8GHz) and X4 810 (2.6GHz). These were the primary focus of the AM3 launch, although AMD also introduced a lower-clocked Phenom II X3 710 (2.6GHz) and OEM-only Phenom II X4 805 (2.5GHz) and X4 910 (2.6GHz) parts. These processors are based on the AM3 socket, but are backward-compatible with existing AM2+ platforms.


The base architecture of the AM3-based Phenom II processors is very similar to the AM2+ models, but there are a few significant differences. The main one is the addition of a dual-mode memory controller that can support either DDR2 or DDR3 system memory depending on platform -- putting an AM3 processor into an AM2+ motherboard defaults to DDR2, while an AM3/AM3 match activates the DDR3 link. The HyperTransport bus speed has also increased to 2.0GHz from the 1.8GHz of the AM2+ Phenom II X4 920 and 940.

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Releasing these AM3 processors so soon after the January debut of the AM2+ Phenom II is a bit strange, especially as AMD reps stated at the time that one major reason for the maneuver was lower DDR2 prices, especially for 2x2GB configurations. That makes solid economic sense, but only a month later and DDR3 is suddenly ready for prime time?

AM3 platform wasn't fully tuned yet,but AMD needed to get its improved architecture out there and show how much more competitive it is against Intel's Core 2 Duo and Quad processors.

Same as the AM3 Phenom II processors are just slight revisions of their AM2+ counterparts, the Socket AM3 platform very similar to its AM2+ predecessor. The big change is the move to DDR3, but as the shift to a dual-mode DDR2/DDR3 memory controller takes place at the Phenom II die level, that has virtually nothing to do with the chipset.

one of the most important results of the AM3 debut is that both AMD and Intel now officially support DDR3, making it the default memory standard moving forward.Having both CPU powerhouses in the DDR3 corner is integral to the overall success and acceptance of this faster memory format.

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By supporting DDR3 memory, AMD erases a perceived advantage that Intel has held since the advent of the Intel P35 and X38 chipsets in 2007.

While DDR2 was (and is) by no means obsolete, AMD's lack of support for the fastest desktop memory hurt the underdog, as Intel used the newer format to set memory performance records with the Core 2 and then obliterate them with the Core i7 and its on-chip, triple-channel DDR3 controller.

AM3 socket

AM3 is AMD’s new socket standard that is built to support DDR3. The good news is that AM3 CPUs feature both DDR2 and DDR3 controllers. This means you can install an AM3 CPU in an AM2+ (and even some AM2) motherboards. You cannot, however, install an AM2+ CPU in an AM3 board. To prevent damage, the AM3 sockets have two fewer pins so you can’t even physically insert an AM2+ CPU in the socket. All Phenom II CPUs except for the two original launch CPUs should be AM3-based.

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Why didn’t AMD make the two original chips (the Phenom II X4 940 and 920) AM3 too? The company said it wanted to get them out as soon as possible and ditching AM3 support a cut quite a bit of engineering time off. We can understand that but it’s only been a month since the 940 and 920 were unveiled so couldn’t it have waited just a little longer so as not to confuse the hell out f people and piss off 940 and 920 owners? Apparently not. In fact, we’ve been told by AMD officials that the 940 and 920 actually had the AM3 controllers in them but they not turned on. If we ever get the time, we’ll have to snip the pins off a Socket AM2+ 920 and see what happens when it’s inserted into an AM3 motherboard.

Conclusion:

These processors are also backward compatible with AM2+ boards running DDR2 memory, which offers a flexible upgrade path for current AMD users. The Phenom II X3 720 is a triple-core processor clocked at 2.8GHz with 6MB L3 cache and 1.5MB L2 cache (512KB each core). It is also a Black Edition processor with an unlocked multiplier for potentially higher overclocking room. The Phenom II X4 810 is clocked at 2.6GHz with 4MB total L3 cache and 2MB L2 cache (512KB each core). Both processors will support DDR2 1066MHz and DDR3 1333MHz memory speeds using a 128-bit wide integrated memory controller.