need a little help

Hi i need a little help batch rendering on a pentium 4, I'm running muster on
two computers 1's an Athlon XP 1.8ghz, and ones a pentium 4 2.4ghz. Currently
the Athlon is kicking the pentiums ass on frames about twenty to one. I don't
get it? I tried another pentium 4 system and have the same results. The athlon
is acting as the server and a workstation, although when using another older
computer (800mhz) as just a server, the pentium behaved identically. The scene
is on a networked drive on the athlon.
The main problem appears that the pentiums sit idle with the batch renderer
using in between 2 and 10% cpu and using 260mb ram (same ram as athlon).
I've eliminated every option from the scene itself, its optimized to the max.
The only two options i'm left with are; 1: the pentiums slower because they are
using the athlons shared drive as a temp drive for the Maya rendering, so all
the calculations are going back and for over the network, obviously i don't want
this, i just want it to download the file and upload the finished rendered frame
if this is the case or 2: the pentiums are slower because they are not multi
threading the scene properly. In which case how do i make the batch renderer
render using multi threading correctly and use maximum cpu.
I have read that task manager sometimes does not report multi threaded cpu's
correctly, but if this is the case then why aren't the 2.4 ghz pentiums faster
than a 1.8ghz athlon let alone 20 times slower? I have also read that you need
to send a job as a single thread job to eliminate this problem but cannot for
the life of me see how you do this with the batch renderer and what are the
flags to do this through the command line. I am using maya 8.5 and the software
renderer. Is this the problem? Surely 8.5's software renderer has been updated
to maximize multi threading?