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I have 4GB RAM installed on my machine, and I'm considering using all of it (IE, installing PAE-enabled kernel). I heard there's a performance penalty for this, so I wanted to know about other's experiences. Should I proceed, or should I remain content with 3GB?

[note] I will be running Linux 2.6.32.

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what is your current memory usage? and what kinds of applications are you running? ones that will use more memory if they have it? e.g. postgres – xenoterracide Dec 9 '10 at 13:06
@xeno top claims that I'm having 200MB RAM available, and 1.6GB cached. That's roughly when I'm running Windows VirtualBox, Firefox, and 3 Java apps (Eclipse, Oracle SQL Developer, and Mule). – Tshepang Dec 9 '10 at 15:46
up vote 5 down vote accepted

If you have a 64-bit processor, an alternative would be to try a 64-bit kernel.

According to this RedHat white paper, a typical server experiences around 1% performance hit, and other tasks suffered a performance hit of 0% - 10%.

In addition to having more available memory, enabling PAE means you have an NX bit, which can increase security.

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But a 64-bit kernel has problems of its own, such as compatibility. I suggest you try out the different options and see which one feels best. – Artelius Dec 9 '10 at 22:03

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