Windows 7: 4Gb memory (2.75 Gb usable) memory remapping in bios causes BSOD

I recently did a new install of Windows 7 64 bit. I noticed windows showed 4Gb of ram (2.75Gb usable). I read tons of articles after googling this and tried several options to free up some more ram.



I have 2 options in bios to change memory remapping over 4GB. S/W and H/W.

When I enable S/W remapping, windows boots everything seems fine but I get a crackling sound from speakers. Bios shows 4Gb (3Gb usable). Windows shows 4Gb ram (3.0 available).

When I enable H/W remapping, windows BSOD during boot, but bios shows 4Gb ram and all 4 Gb available.

So, does anyone have any suggestions as to how to eliminate the BSOD after enabling H/W memory remapping? Try installing Windows 7 again? I read some people saying bump up the voltage on ram perhaps? I've never done any overclocking, but would try if someone thinks it may help.

I've tried several different setting. Any help would be greatly appreciated.

This sounds almost like a bios memory compatibility issue to me.
Have you tried checking the ram in both modes using memtest?
RAM - Test with Memtest86+
Since the memory is obviously the center of this I think it bares testing.
Keep in mind you'll need several passes each way with memtest to get any kind of accurate result and will take some time

Shortly before installing windows 7 I ran memtest on both sets of my memory. I paired them up and ran memtest 2 sticks at a time over night with no errors. I have never ran memtest on each stick individually.

After your suggestion I decided to run memtest on all 4Gb at the same time with both S/W and H/W remapping enabled. This is the only setting bios will show all 4 Gb usable. Within 5 seconds of the memtest start, the system will reboot.

I am going to run memtest with all 4 sticks in and S/W and H/W remapping disabled overnight tonight, but I'm betting it will be fine. Do you think I should try with just S/W or just H/W remapping enabled?

I'm really starting to think it likely there is a bios update for your motherboard to deal with this.

I think you may be right. I am running the lastest bios released from Asus (bios 1016). With all my googling around I found that people with my board A8N-SLI Deluxe have been able to flash bios from a Premium board. Several people have commented about how they don't understand why Asus doesn't put this on their website. Running the Premium bios adds better support for memory modules as well as adds a couple more overclocking options.

ASUS A8N-SLI Bios Mod

I'm going to try this bios out. I will let you know as soon as I find something out. Thanks a million for the help so far.

I successfully flashed my bios to the premium bios. Bios shows 4Gb of memory (all usable). S/W and H/W remapping was enabled by default under new bios. Crossing my fingers, I let Windows 7 boot up. Windows 7 shows 4 Gb of ram (all usable). So far so good, but experiencing some crackling sounds in speakers. I'm going to play around with my drivers to see if I can fix the sound problem.

No luck getting the sound fixed with different drivers. Seems to be a common issue with my board with nforce 4 chipset, a Creative soundcard and Windows 7. I got frustrated and yanked the soundcard out and went back to onboard sound which is working fine.

Windows is running great, shows all 4 Gb of memory usable, didn't really fix my sound issue, but found a way around it. I'm happy. Thanks again for your help Maguscreed.