8GB not recognized by OS X [P55A-UD4P]

SETUP:
GA-P55A-UD4P [F8]
Core i5 750
Corsair XMS3 8GB (2GBx4) DDR3 1600
Gigabyte GeForce GTS 250 1GB
2x 500GB WD Caviar Blue

So I built my setup mainly to have 8gb because I do a lot of Photography work.

When i initially bought the machine and got it working, I had the known P55A-UD4P 'pickiness' of the motherboard only recognizing 2 dimms of the 4 availble dimms allowing for only 4gb to be enabled (8gb recognized but only 2 dimms enabled). It was a really gay experience because I bought 3 sets of memory trying to see if it was an issue with the sticks or motherboard and after that whole process I ended up having to send back the MOBO and CPU.

After getting the new MOBO (same P55A-UD4P) and CPU (Core i5 750) I tested the RAM and it now recognized all 4 dimms, 8GB enabled. So I thought I was good to go. Re-installed and now I am facing the same problem, but now only within Mac OS X.

About This Mac:

Processor 2.67 GHz Unknown
Memory 4 GB 667 MHz DDR2 SDRAM

Ive searched on the forums trying to see if there was any solution for this problem and I havent found any. I even thought it might be because my OS X is not booting in 64bit mode, but I cant even boot into 64bit for whatever the reason. I used the newest method to install (iBoot + NEWEST multibeast (gigabeast)) and I installed the 64bit kext and even tried the force64 command in the com.apple.Boot.plist BUT nothing works. I cant boot into 64bit, if you could help with that as well, itd be much appreciated.

SO PLEASE help me. I need to fully utilize my 8GB. Thanks in advance.

BTW all 8GB are recognized and enabled in Windows 7 64bit

try running geekbench. im running in 32-bit mode with 8GB of ram. the 4 GB max for 32-bit is a windows limitation not osx. also, did u enable HPET 64-bit in your bios? what does your system profiler say?

Yeah i've heard that 64bit and 8GB limitation is not an issue with OS X.

I have enabled HPET to 64bit in BIOS but I havent run geekbench - ill do that once I get back to the house.

I also read in a 10.6.3 successful install on a P55A-UD4P that the CPU model was missing from 'About This Mac' and the way he fixed it for an Core i5 750 was to add this to the smbios.plist:

<key>SMcputype</key>
<string>1537</string>

I think if I fix the CPU recognition it might fix the 8GB issue.

I'l also get geekbench and run some diagnostics when I get back. Thanks for the advice, keep you guys updated.

BTW why did you choose to have your comp recognized as a iMac instead of a MacPro?

fisdj said:

I also read in a 10.6.3 successful install on a P55A-UD4P that the CPU model was missing from 'About This Mac' and the way he fixed it for an Core i5 750 was to add this to the smbios.plist:

<key>SMcputype</key>
<string>1537</string>

I think if I fix the CPU recognition it might fix the 8GB issue.

Click to expand...

i always thought About This Mac was cosmetic. if it still says you have 4GB ram when you run Geekbench, then check your Abouthismac.strings.

fisdj said:

BTW why did you choose to have your comp recognized as a iMac instead of a MacPro?

Click to expand...

i followed a guide from one of the members which had the same board as me so i just went with it. i heard you're also supposed to pick the mac that closely resembles your own pc. the new imacs have core i5 and i7 processors and the only difference was that the imacs had slightly slower ram.

I figured out why the 8GB wasn't being recognized and It's actually pretty dumb from my end. I was continually booting up thru the iBoot CD and not thru the HD where OS X was installed. I was doing this because I had one HD partitioned to have OS X and Win7 on it and if I didnt boot with iBoot then it would automatically boot in Win7. Now I have two dedicated HD's for Win7 and OS X so when I tried to normally boot thru the HD with OS X all 8GB were recognized. I guess iBoot forces only 4GB when you boot with it. Though System Profiler still doesnt recognize my CPU even after I added the string in the smbios.plist.

sephiroth said:

i always thought About This Mac was cosmetic. if it still says you have 4GB ram when you run Geekbench, then check your Abouthismac.strings.

Click to expand...

I'm going to have to try that to fix the CPU recognition, even though it really is cosmetic.

sephiroth said:

i followed a guide from one of the members which had the same board as me so i just went with it. i heard you're also supposed to pick the mac that closely resembles your own pc. the new imacs have core i5 and i7 processors and the only difference was that the imacs had slightly slower ram.

Click to expand...

I see yeah that does make sense. I went ahead and intalled with the iMac this time around instead of the MacPro.

Thanks for all the help man!