Is it possible to boot compressed kernels with a compressed initrd with PXELinux?

First, a little background:

We created a custom Linux distro, for diskless OpenCL computing nodes. We want those nodes to fetch their OS from the network. Our Distro is composed out of a kernel (duh) and a large initrd which is loaded into RAM and everything is executed from there.

We chose to run everything off the initrd for two reasons:

* NFS was not an option to serve the filesystem's extra contents
* Fast file access from RAM.
* No persistent storage needed, data and config is pulled dynamically through a SOAP service.

Now our initrd is about 450M in size. At our network speeds, it takes about two to three minutes to load a single client. Will compression speed up te downloading, and if yes, which one should be used? Is LZMA supported by PXELinux, or do we need to stick to bzip2 or gzip?

Because of the 2-3 minutes loading time, booting 15 nodes over the same network link takes quite a lot of time. We decided not to use hard drives or CD/DVD drives, for financial reasons (cheapest HDD @ €30 times 15 is a lot of money saved ;-) )

So, our question is: what compression options are available for this setup? And how do we do this?

Thank you for your time!

Yvan Janssens