Question : Problem: Upgrading to 4GB of RAM in Vista laptop...Error

I recommended an Acer Laptop to a friend, who went ahead and purchased the unit.  It came with only 1GB of memory, so he bought a 4GB upgrade "kit" (2x2GB so-dimm pc5300 chips).  He pulled the single 1GB chip out last night and installed the two new 2GB chips.  When he booted Vista, it gave him some sort of error/stop/blue screen thing (I wasn't there to witness it).  Vista complained that it couldn't "fix" the problem...  I told him to take one of the 2GB chips out and leave the other one in.  He did that and the computer booted just fine.

My question is, is there likely some sort of BIOS setting or some other "thing" we need to do in order for this laptop and Vista to "allow" 4GB of physical RAM?  I know that in XP, and I think Vista is the same way, you will never get a full 4GB of physical RAM due to the other devices (video card, etc.) needing RAM allocation.  This is Vista 32bit by the way.  The Acer laptop is the Aspire 9420.  The specs say it can go up to 4GB max, but it didn't seem to work.  Any ideas?  I am headed over there tonight to see if I can troubleshoot...just looking for other advice.

Answer : Problem: Upgrading to 4GB of RAM in Vista laptop...Error

"... Are you using dual-channel support SO-DIMM? " ==>  There's no such thing as "Dual Channel support SO-DIMM".   The comment that the laptop supports dual channel simply means that if you install two matching SO-DIMM's the memory subsystem will operate in dual channel mode.

If you install one 2GB and the original 1GB the system should work --> but the memory subsystem will be in single-channel mode.   (Some memory controllers support a hybrid mode which will give you some of the benefits of dual channel for the overlapping parts of the two modules in this combination)

Be sure the modules are properly seated ... and be sure you're VERY "static sensitive" when handling them.   It's easy to "blow" a memory module with a bit of static.

The kit you bought is the correct specification for this laptop ... so if your sure the modules are seated correctly, the system SHOULD boot just fine.   I'd make a bootable CD with MemTest-86+ and take it with you ... boot to it with both modules installed and see if the memory tests okay.   One other thing you can try if the BIOS has the option (not all do) .... disable dual-channel mode and force the memory to operate in single channel mode.

MemTest86+ is here (download the .ZIP of the bootable ISO; extract it; and burn a CD from the image):
http://www.memtest.org/