AMD Sempron 3100+: The best value processor yet

SOMETIMES AMD pulls a lion out of the bag instead of the proverbial cat. The Sempron family could have been seen by most reviewers as a bunch of rebadged Thoroughbred CPUs destined at helping the channel getting rid of the last batch of Athlon XP processors. That's what in a nutshell, most of them are, from the Sempron 2300+ to the last Sempron 2800+. Basically, 333MHz Socket A Athlons with 256KB cache, in some cases. Actually, some online retailers are even rebadging on the fly, Barton Athlon XP processors to Sempron 3200+.

In Detail
The Sempron 3100+ on the other hand is a brand new product and put some spice in the whole line. It is the first member of the Paris family, itself a derivative of the Newcastle family which include the first Athlon64 2800+. The three main notable differences between the Sempron 3100+ and the rest of the Athlon 64 family concerns the amount of L2 cache, 256KB instead of the usual 512KB or 1MB cache, the fact that it has a single channel DDR memory controller and a single hypertransport Link and the fact that it has no AMD64 capabilities but will include the NX bit and Cool'n'quiet features. The Sempron 3100+ is built using a 130nm SOI process, like most new AMD processors, and it has been positioned against the Intel Celeron family.

The Sempron 3100+ has only 68.5 million transistors. In comparison, the newest P4 Prescott has 125 million and the Athlon64, 105 million. The Geforce 6 has more than thrice this amount at 222 million. The number of transistors is almost proportional to the die size at a constant manufacturing process. The Sempron 3100+ die size is 144 mm2. This is less than the AMD Athlon 64 but much more than the older Athlon XP family. Hence, it will still cost substantially more to manufacture the Sempron 3100+ as compared to its younger brothers. Things will be better when AMD moves the manufacturing process to 90nm. It runs at a slow 1.8GHz, earning it a 3100+ PR. Interestingly, it will consume only 1.4v and dissipate only 62W, not that far from the 47W a mobile Athlon XP 2600+ releases when powered on.

Performance
It depends what is being compared to what. In the same price range, you will get the AMD Athlon XP 3200+ featuring a 400MHz bus and a full 512KB cache - already a serious competitor at $120, then you have also the Intel Pentium IV 2.4GHz featuring a 533MHz and one MB cache - four times the Sempron's amount - for only $116. You have three very competitive processors which unfortunately have not been directly compared. As for the Intel Celeron 335D which is supposed to be the direct competitor of the Sempron 3100+, it retails for $108 only.

Overclocking is a little problematic as the multiplier is locked at 9x. Some however have succeeded in adding 450MHz to the 1.8GHz stock speed. The result was worth it. An overclocked Sempron 3100+ will easily give a run for its money to an AMD Athlon64 3200+.

In the market
The Sempron 3100+ retails at $123 at Monarch Computers and for $1 more at Xtremegear and Newegg, both in the US, and in OEM and Boxed. The fact that the processor is a socket 754 product has made its adoption even easier. You can now buy any Socket 754 motherboard and just plug the chip in. You can buy the Athlon64 2800+ for slightly more at $137 for an OEM version. Of course, the latter comes with twice the cache and full 64 bit capabilities. In the UK, the boxed version goes for £73+VAT at Ebuyer while the A64 2800+ - OEM version - costs a mere two quid more at Komplett.

In mainland Europe, the box version goes for €125.13 at Atelco in Germany, while the best deal in France comes from FBIO at €129.90.

However, the situation for motherboards is not as bright. While you can find refurbished Socket 754 mothreboards for less than $50, most of them hovers over the $70 limit which makes the bundle not that much attractive at just over $200. In comparison, you can get an AMD XP 3200+ bundle for less than $160, quite a margin indeed! But things can only improve as volumes pick up and price per unit decrease. The fact that it is compatible with DDR memory and do not need anything like DDR-2 or any other exotic components make the whole platform particularly attractive to those who want to build something cheap and powerful.

The Future
The future is bright for AMD's "Always ON", while the Socket A is finally put to rest, AMD is going to come forward with socket 939 Sempron processors as market demands. 3000+, 3200+, 3400+ and 3500+ versions are already roadmapped for soon. With improved manufacturing process, one can be sure that the Sempron will be alive and kicking for much longer than the Duron. Playing on cache size, FSB and in a very near future, the fact that it is monocore, AMD will make sure that the Sempron remains where it is supposed to be - at the bottom end of the chain. It will also be interesting thing to watch the Sempron 3100+ successors grow in a mobile environment. Sources confirm that the Mobile Sempron, 3100+ onwards, will come with the NX bit feature.

Conclusion
Depending on which side you are standing, you can come to two different conclusions. First, some might say that the Sempron 3100+ is akin to an Athlon 64 "lite" with no upgrade possible other than chucking the processor away. They might even say that to a certain extent, the Sempron is going to cannibalise the Athlon64 sales even more. However, if you're a type A sort of person, then you will say that AMD has decided to rule the market through divide and rule.

Basically, AMD has set enough differences between the mid-range and the lower end for customers to be easily guided by their own reasoning. While the fact that several processors share the same speed grade - Athlon 64 2800, Sempron 2800 and Athlon XP 2800+ for example, gradually, with speed increase, only two families will remain. The gradual transition will finally bring about what AMD really wants, socket 754 for value minded customers and socket 939 for enthusiast. If you want to purchase a value computer right now, the Athlon XP 3200+ would probably be a better bet if you don't plan to upgrade. It costs less and has an overall support - read cheaper and better performing motherboards. But it is a dying race and the Sempron 3100+ is where your money should go in two months or so.

Did you know?
Sempron.com is the property of Andrew David Dawson who registered it back in 2001. Actually, there is no website at this address, only a namebargain start page. Shame that AMD did not get its hand on a proper name with a domain.

Most Sempron 3100+ processors share the following code SDA3100AIP3AX ABAEC 0418SPAW Y884613F?????. µ