If a vendor offering a soft-core product were to list cost/MIPS, that would be useful. Using a very costly FPGA technology in order to be able to advertise a high speed, without offering the cost consequence in moderate, say, 1k, quantity is misleading. Just as an example, a core can be made to perform very well in a very large, very costly FPGA when its ROM and RAM are internal. However, if it uses external resources, costing MUCH less, the performance can go down by at least one order of magnitude, and sometimes two, and the cost reflects that.

It's reasonable to say, "In <name of FPGA technology> the <name of core> executes <number of MIPS> when executing <provide details of code, e.g. Dhrystone v2.1> as compiled/assembled using <name and version of toolset, with parameters, and providing all relevant details>." It's misleading, though it's common industry marketing practice, to omit any part of that.

RE