PAE kernel on 32 bit only CPU

[ThirdOfSix]

If I give family and friends a remaster of my machine which is running a PAE kernel, is their machine going to run noticeably slower with the PAE kernel as compared to the standard kernel?

I showed one of my brothers the latest release of kde and of course the first thing he asked about was if it would recognize all 8MB of his installed memory.

I decided not to ever show him a liveCD that does not have the PAE kernel.

I then used my new remaster with PAE kernel to install the system on a friends old celeron based laptop and it runs fine both as a livecd and installed.

I am just wondering if there is a measurable slowdown on that machine due to usning that kernel.

[T6]

pae kernel just enables a cpu with pae extensions to run those extensions, if those extensions are not present, specially more than 4 gbs of ram, supposedly nothing will happen, the extensions will not be loaded

[Just17]

A pae kernel can cause problems with some older hardware, which I believe influenced the decision to release official ISOs with the standard kernel.

There was some work being done on dual kernel remasters, but I don't know what happened ...  it would have allowed a standard and a pae kernel to be available for selection at boot.

[DeBaas]

I found the standard pae kernel from "the other" 12.04 distro won't start on non pae supporting older PC.

[T6]

my older semprom supposedly is not pae, once it booted a older kernel, will try again but if you guys tell it, then it probably is better not to use it on older hardware and avoid surprises

then, you could do a remaster with a bds kernel and another with a pae.bfs kernel to share with your family

[menotu]

If you run the command

cat /proc/cpuinfo

and then look for the line for flags and if pae is supported it should be shown - similar to this


flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow extd_apicid pni cx16 lahf_lm cmp_legacy

=============
From wikipedia

http://en.wikipedia.org/wiki/Physical_Address_Extension

To use PAE, operating system support is required. Intel versions of Mac OS X support PAE. The Linux kernel supports PAE as a build option and most major distributions provide a PAE kernel either as the default or as an option (Red Hat Enterprise Linux 6+ kernels expect PAE). FreeBSD and NetBSD also support PAE as a kernel build option.

Microsoft Windows implements PAE if booted with the appropriate option, but current 32-bit desktop editions enforce the physical address space within 4 GB even in PAE mode. According to Geoff Chappell, Microsoft limits 32-bit versions of Windows to 4 GB as a matter of its licensing policy,[2] and Microsoft Technical Fellow Mark Russinovich says that some drivers were found to be unstable when encountering physical addresses above 4 GB.[3] Unofficial kernel patches for Windows Vista and Windows 7 32-bit are available[4] [5] that break this Microsoft enforced limitation, though the stability is not guaranteed. These tools increase the RAM limit of the 32-bit version of Windows 7 to 64 GB.

For 32-bit application software which needs access to more than 4 GB of RAM, operating systems may provide some special mechanisms in addition to the regular PAE support. On Windows this mechanism is called Address Windowing Extensions.

[T6]

my atom cpu is pae    a shame the slot can only take 2 gbs of ram, i don't need more than one but i always want more