Duel of the Titans: Opteron vs. Xeon

Details On The Opteron Core: An Enhanced Athlon, Continued

Apart from new features such as the integrated memory controller and the enlarged L2 cache (1 MB, 16-way associative), the rest of the features remain largely unchanged. This can be seen in our photos comparing Opteron to the Thoroughbred core.

As was previously the case, there are nine function units (3 ALU, 3 AGU, FADD, FMUL and FMISC - three integer units and three floating point units) and three x86 decoders -tried and true design cherished by AMD. Almost untouched are the L1 caches for data and commands with as size of 64 kB each, although now an ECC circuit has been added.

Looking into the heart of the matter: a view of the CPU core without the L2 cache and memory controller. The next image explains why you should care.

A comparison between the core images of Opteron (left) and the old Athlon with the Thoroughbred core makes it seem as if almost all units are identical at first glance. You can see AMD only made small changes to the details of its architecture with the Opteron - apart from the memory controller and the L2 cache, of course.