AMD Athlon 64 for Socket AM2 (part 2)

Quite recently, we got the idea of pros and cons of migration of AMD Sempron processors to the Socket AM2. That time, we noticed some insignificant performance boost - wherever found - and the change of the ratings system. Today, we are going on with the excursion around Socket AM2 and looking at what it has given to the regular (single-core) AMD Athlon 64 processors.

AMD Athlon 64 AM2

Recall that migration to Socket AM2 was needed to make it possible for AMD processors to handle the faster DDR2 memory thus increasing the performance of the system on their base. Unlike the value-sector Sempron line, Athlon 64 processors have not only acquired support for DDR2-400/533/667 but DDR2-800 as well. In all the other respects, no other essential changes have occurred neither in terms of the architecture no in the rating systems.

Recall the main specifications of the new and outdated processors in the form of tables:

Athlon 64 Socket AM2

Athlon 64 Socket 939

Athlon 64 Socket 754

As can be seen from the tables, acceleration of the memory subsystem has not affected the rating system. But the product line has been reduced. This is in part caused by the departure from manufacture of more expensive chips having 1 MB L2 cache which used to be quite effective competitors to Athlon 64 X2, especially at games. Besides, there is the trend that early next year the whole line of Athlon 64 processors may be expelled by dual-core X2 whose prices for the lower-end models (Athlon 64 X2 3600+) may reach 100 $ by the end of this year. At the same time, Sempron processors will also turn dual-core and expel Athlon 64 from the low-end. But let us not bury the pretty new processors yet.

If we compare the dimensions of boxes, then the package for AM2 has turned more compact - which is a positive sign because it will be more amenable to carry many processors.

Inside the package, we found the following: the CPU, the renewed cooler, a user's manual, and a logo sticker - nothing of a surprise.

As was already note, the renewed processors offer very little changes. From the top, they can be seen from the marking which now looks as ADA3200IAA4CN. The marking can be read as follows: ADA – Sempron for workstations, 3200 – the CPU rating, I – type of the packaging 940-pin OµPGA (Socket AM2), A – varying supply voltage of the core (~ 1.25-1.35 V), A – the variable maximum admissible temperature (~65-69°C); 4 – the L2 cache size 512 K, CN – the Orleans core.

From the bottom, the Socket AM2 processors is already easier to distinguish by the extra pin (on the photo it can be found on the right-hand processor in the bottom-left corner).

Here is a complete info summary of the processor being tested and the used memory GEIL DDR2-800, according to the CPU-Z utility.

For comparison, we also bring in the info on AMD Athlon 64 3200+ Socket 939 with DDR-400 Hynix.

Overclocking

We were able to overclock the tested specimen of Athlon 64 3200+ having a standard "boxed" cooler to 2700 MHz from scratch, but further buildup of clock speeds resulted in the drop of operating stability of the system.

At the same time, we were able to start up the GEIL DDR2-800 modules in the DDR2-900 mode, albeit through raising the Command Rate to 2T.

Benchmarking

To compare the performances of Socket 939 and Socket AM2 platforms, we assembled the following test systems which, apart from the processors, differed in motherboards and RAM.

Test configuration for Socket 939:

Test configuration for Socket AM2:

Prior to comparison of Athlon 64 Socket 939 versus Socket AM2, we decided to investigate how sensitive the latter are to the memory operating frequency. To this end, using the BIOS settings we turned DDR2-800 into DDR2-667, DDR2-533 and DDR-400 (with the latency timings set as per SPD) and investigated how the performance changes in so doing.

Here are the results which we produced:

Judging by these results, the acceleration of memory from DDR2-400 to DDR2-800 in most tasks gives a 10-20% performance boost, in 2-5% increments between each DDR2 standard.

We leave the most powerful mode, i.e. DDR2-800, and compare it versus the "old" Socket 939 platform equipped with DDR-400 (3-3-3-8). To start with, here are the results for synthetic tests:

Since the CPU core has not undergone changes, the performance does not change much, even under substantial acceleration of the memory. Judging by the results of synthetic tests, for Socket AM2 we can expect a small performance boost in only resource-intensive applications which are demanding primarily for the speeds of the memory subsystem whose increased clock speeds are eaten up by the raised latency and probably some shortcomings in the memory controllers. Now move on from synthetics to practice:

Among the typical multimedia tasks, only the video encoding is the winner, albeit at the minimum positive result as much as +1%.

But using CAD/CAM systems will be a bit more comfortable which can be felt in not only the tests – we found one of the areas where Socket AM2 and DDR2 will prove useful not only theoretically.

The gaming synthetics by Futuremark was unable to enjoy all the pleasures of DDR2, so it is unlikely to expect essential performance boost in games, unfortunately.

We had a surprise in Quake 3 which proved very sensitive to the memory latency and revealed imperfection of the memory controller. The test became a smooth transition from synthetic tests to the results produced in modern games.

The Socket AM2 platform disappointed us a bit by the drop of performance at games – although the result is not much worse and in some ways the same, but not that as we expected.

Final Words

As our tests have shown, AMD Athlon 64 processors after acquiring support for the faster DDR2 memory have not only added performance in most tasks but even lost it a bit. Therefore, it makes no sense to recommend moving to the new platform. But while assembling a new system you will have to think twice and answer the question: «Is that the final system configuration or am I planning for upgrade in some time?». If in some time there rises the need to replace the processor, say, with a dual-core CPU. and add more memory, then the Socket AM2 system will be more promising - it will be not only cheaper but easier to upgrade. Besides, already now Socket AM2 has given a performance boost in some tasks.

We appreciate LLC PF "Servis" (Dnepropetrovsk, Ukraine) for the processors and other hardware presented for tests.