This requires drivers, etc., that normally are OS-level issues. On some Unix platforms the resulting info may be available in the /proc system.
<pre>
<?
readfile('/proc/cpuinfo');
?>
</pre>
On one of my systems I get
processor : 0
cpu : 740/750
temperature : 26-28 C (uncalibrated)
clock : 400MHz
revision : 130.2 (pvr 0008 8202)
bogomips : 796.26
machine : PowerMac1,1
motherboard : PowerMac1,1 MacRISC Power Macintosh
L2 cache : 1024K unified
memory : 128MB
pmac-generation : NewWorld