I'm writing a specification document for a whizz-bang Web 2.0 application, and I want to make sure that the client is not mislead into thinking that the jQuery animation / AJAX bits will be smooth for any visitor on their dodgy old DX-66.
I considered taking the Firefox 3 requirements (Pentium 500MHz, 128MB RAM) but that isn't going to provide a sexy Web 2.0 experience. What minimum hardware specification would you recommend for today's modern web apps?
why don't you just put some standard office PC in the last 2 years time specs? some >= 1,5 GHz processor of any kind & 512 MB RAM should be something not too expensive and pretty common today in most environments.
This is one of those areas where we don't specify, and for good reason. The experience can be so drastically different between browsers, versions and OS, that it is impossible to give concrete performance promises. I typically state the minimum system requirements for the functionality to work, and that is always the same as the JavaScript library I use. So I just pull from jQuery's specs. You will know when a vast majority are experiencing performance issues, and a lot of times that means an ongoing adjustment, not a one time fix... more like a give/take.
EDIT:
Think about this way... how fast of an animation is fast enough? If your drag/drop lags, how much lag is okay? If it is slow on Safari, but fast on Firefox on a particular system, then do you blame the OS, or the browser, or the processor? When you combine the three, you are talking about increasing the complexity of your testing plans exponentially.
It's possible to write a very simple application that will bring a 3GHz powerhouse to its knees. And it's also possible to write a very complex, featureful application that runs on an old 1GHz Celeron with minimum slowdown. There's no way we can give a specific set of requirements based on the technology, it depends on your application and how it is written.
My suggestion is to pick a speed, and then buy an old computer (something that was top of the line 4 years ago perhaps) that runs that speed. During development, test on the old computer regularly to make sure it works. Set that as your official minimum specs.