I'd go for the Athlon - particularly when you consider that over the last few years, many benchmarks have been under-reporting the speed of AMD processors, due to a DELIBERATE bug in the Intel compiler which is frequently used to compile the benchmark tests. Turns out that Intel's compiler checks the maker ID of the CPU and deliberately selects highly optimised code if the result is Intel, and deliberately de-optimised code if it's and AMD or VIA. Part of the antitrust settlement between Intel and AMD is that Intel must undo this deliberate sabotage. Simply faking the ID to make an AMD or VIA appear as an Intel chip can improve the benchmark by up to 47%.
Here is the wording from the AMD-Intel settlement:
"Requiring that, with respect to those Intel customers that purchased from Intel a software compiler that had or has the design or effect of impairing the actual or apparent performance of microprocessors not manufactured by Intel ("Defective Compiler"), as described in the Complaint:
1. Intel provide them, at no additional charge, a substitute compiler that is not a Defective Compiler;
2. Intel compensate them for the cost of recompiling the software they had compiled on the Defective Compiler and of substituting, and distributing to their own customers, the recompiled software for software compiled on a Defective Compiler; and
3. Intel give public notice and warning, in a manner likely to be communicated to persons that have purchased software compiled on Defective Compilers purchased from Intel, of the possible need to replace that software."