Kuma’s Last Gasp

Today AMD has released what looks to be the last, new 65 nm Phenom based processor.  The Athlon X2 7850 is a 2.8 GHz dual core processor based on the 65 nm/B3 Phenom core.  It is rated at a hefty 95 watts, though it likely rarely hits that at even full load.  It is a Black Edition processor, which means it has its multiplier unlocked and users are allowe easy access to overclocking.  The 7850 is derived from a full quad core, but two of the cores are disabled for this particular model.  There has been some evidence that these extra cores can be unlocked by using ACC on motherboards that support that feature (read SB750 southbridge based products).


The best part of this release is the price that users will be paying for the 7850.  $69 plus some tax and shipping will get a consumer a fast dual core processor which should satisfy most of their productivity and gaming needs.  In fact, AMD is really excited about what can be had at the price points that are available for many of their parts.  Damon Muzny at AMD was kind enough to dig up some prices.  A Foxconn AMD 770 based motherboard with the SB700 southbridge will set a user back $54 after rebate.  While overclocking may not be fantastic for this board, it does make for a solid foundation for a gaming/productivity system that can be had for under $500 (including OS).  Combine that duo with some inexpensive DDR-2 memory at either 800 MHz or 1066 MHz speed (can get either for under $50), and for approximately $170 the user has the basis for a pretty interesting system.  The recently released Radeon HD 4770 of course comes to mind when thinking about budget gaming, and another $99 here sets the user back $269.  Add in a case, power supply, hard drive of choice, DVD writer, and an OS… and having a secondary machine with this power for under $500 is pretty impressive.

Global Foundrie’s 65 nm process is very mature now, and they have stopped adding any enhancements to it for some time (as they are focused on 45 nm now, as well as the upcoming 32 nm bulk and specialized processes).  Do not expect this core to give overclocking results greater than what was achieved with the earlier X2 7750.  I have seen results around the 3.3 GHz range, but mileage will vary depending on cooling and overclocking expertise.  This particular processor does compare very well to what Intel has available at this price point.  The E5300 does have one advantage though, and that it is based on Intel’s 45 nm process, and its overclocking ability is likely a bit higher overall.

The advantages that the X2 7850 have over the E5300 deal mainly with how they handle memory transaction.  The X2 has a larger overall cache size, plus the integrated memory controller.  The X2 has a total of 128 KB L1 (divided between data and instruction), 512 KB of L2 cache per core (1 MB L2 total), and the full 2 MB of L3 cache.  The E5300 contains 64 KB of L1 (again divided between data and instruction) and 2 MB of shared L2 cache.  No L3 cache, and no IMC.  These are of course not deal breakers for the Intel part, as overall performance between the two processors is essentially a wash.  Only in very memory intensive operations will the X2 show a performance increase over the E5300.


Where the X2 really has an advantage is in gaming.  Most games love large caches, and between the extended L3 cache and the IMC, the X2 7850 is the superior gaming chip.  The outcome may have been different if the E5300 had the full 6 MB of L2 cache, but that would then turn the processor into a much more expensive part.  Consider that the E7400 is a 2.8 GHz part with 3 MB of L3 cache, and it sells for $119.  Far more than either the X2 7850 and the E5300.  To get the full amount of 6 MB of L2 cache on an Intel part, a user needs to pay $168 for the E8400.  Which is far more expensive than the X2 7850 AND a decent motherboard.

Motherboard support for both Intel and AMD for under $109 is surprisingly robust.  My personal opinion is that AMD has a small edge over Intel, but that edge is razor thin.  AMD has a good selection of their own chipsets ranging from the 790X to the 740G, while Intel features their P45 chipset down through the G31.  For integrated chipsets AMD does have a large advantage in terms of performance and compatibility, but when it comes to budget enthusiast boards they both come in very competitively.  NVIDIA also has a smattering of chipsets for both sides, and it does flesh out the lineups quite nicely for either CPU manufacturer.


When it comes to maximizing a user’s overclocking potential, then seeking a motherboard in the $90 to $109 range will prove to be the best proposition.  Getting a 770 based board with a SB750 southbridge would be the bare minimum, as it enables use of ACC and allows the X2 to be clocked higher than a non-ACC enabled motherboard.  The largest selection of ACC enabled parts will likely be the 790GX boards, and these again span the $89 to $149 range.

If there was one downside to this release, it is that the Kuma is not AM3 compatible.  It is only available in AM2+ form, as the memory controller on Kuma does not support DDR-3 memory.  So for now, the lowest end AM3 part is the X3 710 which retails for around $119.  From all indications though, AMD should be releasing a 45 nm dual core part in the next two months which will satisfy the AM3 market.  But for today, AMD’s fastest dual core part is the X2 7850, and at $69 it does not disappoint with its performance and features.

I will be exploring the budget nature of AMD’s latest offerings soon, so stay tuned!