Sun Ultra 5 Overclocking

Gain some Mhz on UltraSparcs: Yeah, overclocking your USII box is very easy, you don't even need to open it. Simply go OBP and play with also hidden nnn at-speed parameters. With .speed you will be able to see how fast you are going (if your box supported the overclock). If the box freezes, turn off and on and try to lower the nnn parameter. My Ultra 5 270Mhz now reports:

bash-2.05# prtdiag -v
System Configuration:  Sun Microsystems  sun4u Sun Ultra 5/10 UPA/PCI
 (UltraSPARC-IIi 297MHz) 
System clock frequency: 99 MHz 
Memory size: 256 Megabytes
========================= CPUs =========================
                    Run   Ecache   CPU    CPU 
Brd  CPU   Module   MHz     MB    Impl.   Mask
 0     0     0      297     0.2   12       1.2

… and so on .. Don't forget to nvstore the also hidden command within your nvramrc !! And also, before going too high, be sure to test the system robustness, you probably don't want your system to do strange things during your daily work … (sadness: tested and verified also in my 333Mhz U10, now running at the top speed also-hidden is capable to set in this machine : 370Mhz)