Review The arrival of AMD's Sempron 3400+ will come as no great surprise to anyone who has heard the rumours about its imminent launch. When it comes to budget processors AMD doesn't normally make big announcements, so those who've not kept up to date with the latest processor developments might wonder what the all the fuss is about, writes Lars-Goran Nilsson.
This time, there's a bit more to the chip than just a clock speed or cache increase - the Sempron 3400+ has been spruced up with some extra functionality. The 3400+ has a 2GHz core and 256KB of L2 cache, half that of an Athlon 64. The core has been shrunk and it's now built using 90nm technology. But what really matters is that the new Sempron core now supports 64-bit addressing and Intel's SSE 3 instruction set. The on-board memory controller has been tweaked, too, though in fact this was first done on the 3300+. According to AMD, the memory controller is more efficient, can handle memory modules of different sizes and if you populate all the memory slots with double-sided modules, the PC2700 speed limitation has been removed.
Up to now, AMD had reserved 64-bit support for the Athlon 64, but with Intel introducing 64-bit support to its Celeron range, AMD had little choice but to follow suit. SSE 3 has been inherited from the latest generation of Athlon 64s making the latest generation of Semprons more like the Athlon 64s than ever before.
The downside is that AMD has not moved the Sempron to Socket 939, so if you're interested in getting the new 3400+ you'll have to stick with a Socket 754 board and a pretty dead-end upgrade path. All the features of the 3400+ will eventually filter down through the various speed grades, although I would imagine that you'll have to wait for old stock to be sold out before they become available. In the meantime, all retail 64-bit Semprons will have clearly labelled boxes, but if you're looking at getting an OEM chip you have to keep an eye of for the product number; it should end with BO or BX for it to be a 64-bit CPU.
According to AMD, the Sempron processor speed ratings are not equivalent to that of Athlon 64 although it hasn't been specific as to exactly how they differ. Rather confusingly, a 3400+ Sempron is not comparable to a 3400+ Athlon 64; it is more like a 3000+, which is also clocked at 2GHz but with a larger 512KB cache. I'm not certain that 256KB of cache will make that much of a difference and, as you will see from the test results, the Sempron 3400+ put in some quite impressive numbers.
Although I didn't have a 3000+ Athlon 64 to hand, I managed to dig out an older 3200+, clocked at 2GHz with 1MB of cache. Although this chip has an extra 768KB of L2 cache to its advantage you'll see that it affects processor performance less than you'd think. However, the Sempron 3400+ has the advantage of having SSE 3, something the older 3200+ Athlon 64 doesn't have and this could tilt the scale to the Sempron's favour in certain applications.
Looking at SYSMark 2004, the Sempron 3400+ scored 160 points overall, whereas the 3200+ Athlon 64 proved that more cache is a good thing with a score of 168 points. This might not sound like a huge difference between the two chips, but I think we'll have to wait for another speed bump or two before the Sempron catches up here. In PCMark 05, the Sempron scores 3148 overall versus 3237 for the Athlon 64, a much smaller gap.
Looking at some of the individual scores in PCMark05, it's interesting to note that the CPU test actually has the Sempron as the winner with a score of 2835 against the Athlon 64 3200+'s 2821. However, this is within the margin of error and the extra cache of the Athlon 64 wins it the memory benchmark with a score of 3077, leaving the Sempron trailing behind at 2869 points.
The Sempron does well in 3DMark 03 compared to the Athlon 64, with a score of 7858 points versus 7998 using a 6600GT AGP card. It might not be the choice for high-end gamers, but it shows that budget processors are not as bad for gaming as they once used to be.
There's little point for anyone to upgrade their current Socket 754 platform to the new Sempron processor, unless you've already got a slower Sempron or possibly a 2800+ Athlon 64. However, if you're looking at building yourself an affordable PC with good performance you could do far worse than going for the new Sempron, especially you are considering moving to 64-bit Windows XP or Vista in the future.
AMD didn't give us a UK price in time for the publication of this review, but all indications points to the Sempron 3400+ costing under £100 - it's $134 in the US. But with a Socket 939 Athlon 64 processor costing just over £100 there seems to be some product overlap in AMD's inventory.
The Sempron 3400+ is a solid processor and it's good to see AMD bringing 64-bit support to its entry-level chip family. The addition of SSE 3 support is welcome too. But as always with a budget product success very much depends on the price.
|AMD Sempron 3400+|
|More info||The AMD Sempron site|