The following link (http://download.intel.com/support/edison/sb/edisonmodule_hg_331189004.pdf) contains the Edison board specifications including the processor type. See section 3.1 for processor info. In summary, the processor is NOT an ARM but it is x86. See Wikipedia for details on x86.
From the documnet:
Intel® Edison takes advantage of the Intel® Atom™ Processor 22 nm System-on-Chip, targeted for the smartphone market segment. The SoC contains dual IA-32 cores operating at 500 MHz. The architecture includes 2-wide instruction decode and Out Of Order Execution with 1 MB cache shared between the two CPU cores. It includes Intel SIMD Extensions 2, 3, 4 (SSE2, SSE3, SSE4.1/4.2).
As far as you issue measuring performance, what specifically are you trying to measure? Memory? Processor? Here is a link to better understand the 'TOP' command. http://linuxaria.com/howto/understanding-the-top-command-on-linux
Hope this helps,