Here it is. Of course it looks pretty much like the old one, because all AMD64 processors are equipped with a metal cover - called a heat spreader - that prevents us from actually seeing the chip. It is attached to the actual die by some thermal pad or compound and it helps to dissipate heat onto a larger surface. It also serves as very efficient protection, since lots of Athlon XP and Duron processors have been damaged by careless installation of the processor cooler. Intel introduced heat spreaders when the Pentium 4 was introduced.
Sempron 3400+ is an unknown processor to CPU-Z, so the core is not displayed correctly.
With the introduction of the 3400+, the Sempron family has a new member, now with 256 kB L2 cache.
If you feel like SSE3 extensions and 64 bit capability is something a low-cost computer does not require, the Sempron 3300+ may be good enough for you. Although the core no longer is state-of-the-art - to the extent that this description applies to budget hardware at all - the thermal properties are basically the same, and performance is not much different either.