Quote:
Originally Posted by linuxfia
Would the performance be a lot better than my present system where it only sees 3 GB?
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That depends on what you do with the system.
If you even need to ask the question, you probably don't have large enough use of memory by processes to cause a lot of accesses to the swap space with 3 GB of memory.
But even if the swap space was never used at all with 3 GB, more memory can cause Linux to do more file caching, which may reduce the number of disk accesses required for file I/O. Depending on what you do with your system, that might make a very big difference or no difference or anywhere in between.
I'm not sure of the exact overall and performance limits of file caching in a 32 bit kernel, but it is limited. If best performance would be achieved by using a large fraction of 6GB for file caching, then I think you need a 64bit kernel to do that. The PAE kernel can allow more file caching than the non PAE 32-bit kernel, but not as well as the 64 bit kernel.
But, if your 3GB system were using a lot of swap space for active processes, then a PAE kernel could make just as good use of the extra memory as a 64bit kernel. Or, if you do so little disk access (file I/O or swapping) that the extra memory makes no difference for that reason, then the 64 bit kernel wouldn't help.
Quote:
Originally Posted by lazlow
unless you switch to a PAE kernel. If you do that you will take a performance hit (translating 32bit to 40bit). If you use 64bit there should be no issue.
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The translation structure is one level higher and twice as wide for PAE than for non PAE 32bit. But the translation structure for 64bit is another level higher than for PAE and the same width as PAE.
Probably you won't notice the performance hit for the increased translation structure. But if you do notice it, it would be bigger for 64bit, not "no issue" for 64bit.
Quote:
Originally Posted by linuxfia
I heard that there's no kernel-PAE anymore but I should install kernel-hugemem. Is kernel-hugemem what I need?
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Hugemem and HIGHMEM64G are both just names for enabling PAE support in a 32bit kernel. Use whichever name for PAE your repository uses or the kernel config GUI uses (if you make a new kernel).