Can't see 4 Gb RAM with ASUS P5B Deluxe / x86_64 Fedora Core 6
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My understanding is that enabling memory remap will provide access to 4GB of RAM but disable the onboard Ethernet adapter when you are using a x86_64 or PAE enabled kernel. ASUS has just gotten the function working with Windows, but Linux compatibility is still pending.
Same on fedora 8 with Asus P5B : 4 GB RAM not seen
I bought a PC with 4 GB RAM and install fedora 8 with kernel 188.8.131.52-42.fc8. The motherboard is an Asus P5B.
1) when I type free (or cat /proc/meminfo), the total memory reported was 3 GB (1 missing). The BIOS was also reporting 3 GB.
2) I went back to the store (dohhh...) thinking that they screw me up... The guy did change the BIOS "Memory Remap feature" to enabled in the Advanced chipset feature. Note that this is not even documented in the P5B user guide.... OK, now the BIOS reported 4 GB. Cool.
3) I went back home, loaded the system and typed free (or cat /proc/meminfo) and now the system was reporting 2 GB (2 missing)..... Arghhh !!!
4) After some googling around, I installed the PAE kernel. My grub.conf look like :
If you are going to use 4GB of RAM, there is really little interest in sticking with a 32 bit system. 64 bit Fedora will recognize all of that RAM out of the box + you won't suffer the performance penalty that comes with using PAE nor the potential hardware issues (some drivers simply don't like PAE all that much).
I have been running 64 bit Fedora with one of those boards and 4GB for over a year now. It used to be pretty problematic because of 32 bit only plugins (macromedia, java, flash, ...) but that is all in the past now. It works just as well as 32 bit.
Well, as I said, I have one of those motherboards and 4GB of RAM. Works perfectly with a 64 bit OS - with Fedora, Mandriva and Solaris, at least. You will run into a little issue with the 64 bit versions of Debian/Ubuntu, though, unless you specify mem=6144MB agp=off as additional boot arguments. If you don't, they simply won't boot.
Anyway, if you're wondering why you see only 2GB, I'll explain: 32 bit systems (without PAE) can access only 4GB of memory. Since part of that memory needs to be reserved for I/O, only part of it remains for RAM (about 3GB). One solution is called memory mapping but since it pushes any RAM above 2GB over the 4GB limit, 32 bit users won't see the benefit: rather than getting more, they will get less (only the first 2 GB that fall within the 4GB area). 64 bit, however, can see way beyond 4GB so it doesn't suffer from such quirks.
No 64 bit flash plugins? Sure but then we've been using nspluginwrapper for over a year now, it works just as well.
Which distribution do you use? Most now have nspluginwrapper in their repositories, a utility that allows people to run 32 bit browser plug-ins even though they have a 64 bit browser. It works with flash, with adobe reader, with realplayer, ... Only the java plug-in is still a bit of a problem but I believe that the icedtea java plug-in works better. You should really give it a try.
The problem with PAE is that it not only has a predictable effect (more overhead and thus a slower system) but a few unpredictable ones. It increases memory space from 32 bit to 36 and not all applications like that kind of tweak very much. Some become unstable, other ones will fail completely. I feel that PAE fully makes sense only systems where you have maximum control over compilation and configuration. Or on a production server that can't be taken down to replace the OS with its 64 bit version. But then servers tend to have fewer applications so the risk of PAE creating issues is usually far smaller than it would be on a home user's computer.
I am not familiar with the WINE thing you referred to. Still, if it's closely modeled on windows xp, I wouldn't be surprised. Microsoft all but ripped out PAE support with SP2 because they were getting too many angry calls from users who were trying to do that on cheaper systems that became completely unstable.
Now, since you are using fedora 8, it should be so easy because nspluginwrapper has been integrated into the repositories. Just do a yum install nspluginwrapper. If you're lucky, things should work out of the box. If not, you can get them to work using the mozilla-plugin-config command. Traditionally, one had to use the nspluginwrapper command but the folks at fedora for some reason decided to rename it; it works pretty much the same, though.