I have seen people on this board make reference to not wanting to put over 100 clients on a RAQ. Is this mainly refering to RAQ3's?

Because I am looking at the configurations of RAQ4's. with 512mb Ram on both. the exact specs of the servers I have seen are

RaQ4 Software
512 RAM - PC100
20 GB Hard Drive
450 MGhz Processor
100GB Data Transfer/Mo

RaQ4 Software
512 RAM - PC100
DUAL 20 GB Hard Drives (Raid 1)
450 MGhz Processor
100GB Data Transfer/Mo

I know the processor isn't 1ghz, but 450 isn't bad and the RAM is what I thought mattered. Would anyone actually put the full 250 clients on these boxes that cobalt allows? Or is cobalts linux version actually that much slower than linux/apache on a regular linux box?

While Cobalt boxes certainly aren't the most powerful machines, they still pack quite a punch.

With 512 megs of RAM, you should be able to easily house 250 normal sites. However, as soon as a web site uses a lot of CGI scripting and gets a lot of hits, things change -- this is why many hosting companies disconnect web sites with high CPU usage.

You should be able to host about 200 SMALL sites with this.
However, if you run a few sites on there that require a lot of CPU (databases, CGI, etc) now THAT bogs down your server.