If it's a small company with a small number of developers then you could argue that the benefits of being able to spec and manage your own workstation outway potential drawbacks.
There are however two significant problems with this approach:
Having centralised hardware means that repairs take a minimal amount of time - you're not going to keep stock of different types of PCI, PCI-e hardware, 5 different graphics cards or 4 different types of DIMM.
Having the developer handle the purchasing relationship reduces the opportunity for discounts (as well as control of software on the network). Margins on hardware are generally razor thin but having 8 different support contracts with 6 different suppliers is a potential logistical nightmare for a company. Even worse, if IT holds the relationship then that's 6 different suppliers for the same class of item that the relationship needs to be maintained with. The extra time used for that is time that could be spent supporting IT.
I realise your problem, but your problem is not that your computer is slow, it's that your compilation isn't distributed.