Identify the speed of memory

dmidecode  is a tool for dumping a computer’s DMI (some say SMBIOS) table contents in a human-readable format.


dmidecode

# dmidecode 2.11
SMBIOS 2.5 present.
30 structures occupying 1372 bytes.
Table at 0x0009D800.

vm.swappiness

vm.swappiness is a tunable kernel parameter that controls how much the kernel favors swap over RAM. At the source code level, it’s also defined as the tendency to steal mapped memory. A high swappiness value means that the kernel will be more apt to unmap mapped pages. A low swappiness value means the opposite, the kernel will be less apt to unmap mapped pages. In other words, the higher the vm.swappiness value, the more the system will swap.

The default value I’ve seen on both enterprise level Red Hat and SLES servers is 60.

step of modify:

sysctl -w vm.swappiness=0 (default: 60)

swapoff -a

swapon -a

ADD  vm.swappiness=0  to  /etc/sysctl.conf

References:
What Is the Linux Kernel Parameter vm.swappiness?
http://overinfinityresearch.blogspot.com/2008/09/ubuntu804.html