8GB RAM: PAE or not PAE?

[Ivan Voras]

err wrote:

> I've a kernel with no modules, and before trying PAE I would know for other people experiences...
> In particular I'm interested in the behavior of ciss, bce, em and usb stuff, and application like Perl, Ruby, PHP 5, MySQL server, heavy MAWK and bzip2 load.

If the kernel runs fine, the applications won't notice anything 
different. I have only one system on PAE, and it works fine, it's a web 
server and I didn't notice performance problems with it.

You'll probably want to try it - save the old kernel, build a PAE 
kernel, and run it. I think USB is disabled for PAE by default but I 
didn't encounter problems with it when I enabled it. AFAIK, if a driver 
is known to work in 64-bit mode, it should also work under PAE.

> Also, if I boot a PAE kernel, in order to have all my RAM available, I have to set the hw.physmem variable to 8G ?

No, the kernel will detect and use the extra memory. Each single process 
is still limited to 4 GB, of course.

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