Note: Because Crucial carries modules with more than one design of FBDIMM-approved heat spreaders, your module may look slightly different from the example shown above. Below are some of the other possible products you may receive when ordering this product.
I even tried booting Type 1 ram by itself, and my PC still refuses to boot.
The two parts are basically the same. When you order online by system information, you are shown what we refer to as an “external” part number, in your case number CT4027395. It is a system specific number and is mapped exclusively to the Lenovo IdeaPad Z400. The longer part number, CT1064BF160B, is the one that would you see printed on your module, and that is the actual module part number, or the "base" part number. There are other specifications to memory than the basic ones published on the site, and they sometimes requires us to filter out a certain build of a part for a specific system. The external part number can accomplish this, since we can build filters into them when necessary. Those filters are also the reason that we can only guarantee compatibility if you order by system; the external part number tells us which computer you are ordering for. If you order by specifications we don't know what model of computer you have, and that makes it impossible to guarantee compatibility.
I am sorry for the issues that you have been experiencing with your memory upgrade. What sort of issues are you having? Is it beeping when installed or not starting all together? Have you tried the memory one at a time? or each pair individually?
Thanks in advance!
I'm trying to find out some more specs for this part:
Specifically, I need to know what LRDIMM Register is being used on this part, I'm hoping it's one of the InPhi GS02A ones like listed on:
But I see that Part number different from what was ordered, so it's hard for me to know.
Being able to download a copy of the SPD would be great as well.
Thank you for contacting us today. Your system actually can use 1600mhz RAM. We have done extensive testing on our end to guarantee compatibility. As long as you are purchasing from the compatibility list you will not have any issues upgrading your RAM.
In some cases manufacturers may not be able to test new memory module speeds after the system has been released, and this may be why you are not seeing this speed listed. Please let me know if you have any other questions or concerns.