Struggling to find the correct drivers for a new build is a perennial issue so I wrote a little utility (https://www-secure.symantec.com/connect/articles/readyutility-assist-identifying-plug-and-play-drivers) that reports on all the Device IDs in any computer running windows, plus associated INF files, etc.
I have found that searching with Google on a specific device ID would often lead me to a valid driver download.
Two things to bear in mind:
1. WinPE, as used in Ghost, is based on the Vista 32 bit kernel so you need Vista 32 bit drivers for addition via Ghost Boot Wizard
2. The drivers needed by your operating system will be whatever the operating system needs and this has nothing to do with the drivers used in WinPE.
Those points aside, if you have a working set of drivers then at some level the driver INF file is being selected as a valid source of driver information for your NIC. Thereafter, any performance issues may be due to a multitude of other factors.
Taking Ghost out of the equation, how does one of these HP machines compare on transfer rates under windows when benchmarked against one of your other machines?
It is easy to blame the NIC driver for all performance ills, while losing sight of the fact that transfer rates also involve the computer bus, memory, and hard disk data channel. Perhaps the SATA drivers for the hard disk are not optimal for the chipset? Perhaps there are additional utilities for the computer chipset that are required to optimise speed?
The transfer rates you quote suggest that you must be running Gigabit LAN. There are different possible configurations which may be mediated by the INF file if is has default settings, so this is why I mentioned this in a previous post.