I have an ata100 hard drive with 2mb cache and I am about to fit an
additional ata 133 hard drive with 8mb cache. Is there any advantage to
making my new disk the primary?
The larger cache helps a little. By itself, it might not be
enough reason to change the drive configuration, BUT this
new drive probably has higher data density and capacity too
so it's STR (sustained transfer rate) as well as latency
could be (usually is with *all else* remaining equal)
better.
However, the most gain will typically be from not merely
making the new drive the primary but partitioning off a
small first partition for the OS, perhaps 6-20GB in size,
depending on your needs.