When I enable either AHCI or RAID mode on the main south bridge SATA controller, I cannot enter the BIOS menu anymore.  I hold delete on startup like normal, but it simply doesn't work.  The only way I can get in is to clear the CMOS.
 
I'm running the latest BIOS version 83.  There is no issue when enabling RAID/AHCI on the secondary (JMicron) controllers.
 
What could be causing this?

thePoison Do you hold it or continue to press it over and over?

I have tried it both ways, but neither work.

Is your mouse a optical mouse, if so look at the botom of it, hit the Delete key as soon as you see the Red LED flash, you can also atempt to hit the key the moment you see either a cap loc or Num lock LED on your key board if you have that.

KMoore4318
Is your mouse a optical mouse, if so look at the botom of it, hit the Delete key as soon as you see the Red LED flash, you can also atempt to hit the key the moment you see either a cap loc or Num lock LED on your key board if you have that.

I have a laser mouse (which does have an LED), and my keyboard also has LED indicators.  I have already tried hitting the delete key very rapidly and holding it down.  I'll try it again with the LEDs in mind when I get home.
 

NordicJedi 
Other than not being able to get into the BIOS, are you able to boot into Windows and operate normally?  Or does the system just hang during POST? 

 
Actually, after POST, my system boots into GRUB as my primary OS is Linux and I dual boot with Windows.  When AHCI is enabled, it completes POST, GRUB stage 1 loads, and then I get GRUB error 17 during stage 1.5 and I'm therefore unable to boot into either OS.  I have built the ahci module into the initrd image, so there should not be any problem on the OS side.  I have been considering this a separate issue -- first I need to get the BIOS working, then I can work on the bootloader.  I may need to install GRUB2.
 
EDIT:  GRUB should be able to handle AHCI with no problem.  The most likely cause of the error 17 is just that the order of the hard drives changes when AHCI is enabled.  That is an easy fix.  Still, that is a separate issue.  I need to be able to get into the BIOS without resetting the CMOS every time.
 
Another extra bit of information:  when AHCI is enabled, the BIOS boot screen appears for a much shorter time.  I also see an additional screen (after the main screen) that displays for only a split second and appears to say something about an "AHCI BIOS."  But it is too quick for me to read it.
 
EDIT 2:  I just tried again and I definitely cannot get into the BIOS no matter what I do.  I can see the numlock led flash a couple times during POST, which makes me think the keyboard is working.  But it just doesn't.  I also found that I can't get into the boot order menu either (by pressing escape).  So it seems like the keyboard just isn't doing anything at all.  Unfortunately I do not have a PS/2 keyboard to try.  But why would enabling AHCI change the keyboard functionality?
 
Thanks for your responses!

By the way, the reason why I am interested in this is because I am going to get an SSD.  So I need AHCI mode.  I can't buy an SSD until this is fixed!

Someone you know MUST have an old ps/2 keyboard you could try?

noahsark1126

KMoore4318
try dropping back to 77some people have had issues with the raid rom in 83. 

I am running 83.  Where can I find a 77 rom?

http://forums.evga.com/tm.aspx?m=659172

USB keyboards can be found for around 15.00. I have a X-58 sli  w/o overclock in AHCI with ssd and optical mouse using USB keyboard. Using 83 bios. No problems getting into bios ! You (Have) to Reinstall Operating System going from IDE to AHCI otherwise you will have problems ! I haven't messed with Linux, but dual boot windows Yes