If developers always have the fastest machines available, how will they test or care about speed? I hope they have automated benchmarks of common tasks at least.
(Although it is obviously good to have things compile as fast as possible.)
(Although it is obviously good to have things compile as fast as possible.)
Honestly, giving your developers a slow machine to "encourage" them to write faster code is a fallacy. The average user is not running multiple databases, multiple IDE's, debuggers, editors, multiple browsers, help documents and all the other programs they require to get stuff done. By all means make the test machine match what the users have but invest (yes it is an investment) in a fast machine for your developers.
If nothing else it will make them feel appreciated which will return more then the $1000 odd it will cost to spec their machine up from your users base model.
Performance tests are done separately on machines on a lab and there's lot of them, with components on and off,different configurations etc. In some cases you can simulate slowness like latency or less bandwidth ,as in a client with a 14.4k modem connection, with things like wansim. That allows to automate as much as possible.