IBM ChipKill memory, problems?

[Don_Komarechka]

Hello, I recently got ahold of some old ChipKIll memory. I have 4x 128mb 50ns 16Mx72 3.3v EDO DIMMs, that I plan on using in a Dual Pentium II OverDrive 333mhz system as a local fileserver. My problem is this memory appears as only 64mb modules to the BIOS. I am running the latest BIOS available for the Intel PR440FX motherboard. The memory seems to operate fine but I am curious as to why I can't use 512mb and am stuck with 256mb. 256 is more than enough but I am just curious if anyone out there has a possible answer or solution! thanks!

[Peter M]

Welcome here!

Every chipset has its limits on how big (storage-wise) the individual RAM chip may be. You've got the typical symptom of when you've exceeded the limits of this ancient chipset.

Your last straw is that the chipset might be capable but the board's BIOS isn't. Locate and update to the latest available, and if still nogo, then that's it.

[mobo57]

That mobo supports 4x128 meg mods.
http://support.intel.com/support/motherboards/desktop/PR440FX/sb/CS-013563.htm
What does it show in the os for memory? Could it just be a quirk in the board how it reports through bios? Have you tested the memory?

[Don_Komarechka]

I have tested the board, though I don't have any other 128mb EDO DIMMs around but my ChipKill ones. It works fine with my old 64mb ECC modules and it worlds fine with the 128mb ChipKill modules but it only detects each as 64mb. its very odd.

[Don_Komarechka]

I have tried manually setting the memory address in memtest86+ to scan 250MB-510MB to see if there is any memory present but it defaults to 250-256 which I guess is the upper ceiling. If anyone has any other suggestions, please let me know.

[Peter M]

You got one "other suggestion". Look for a BIOS update to the board, and that's it then.
Not all "128 MByte" DIMMs are created equal. Some are made from older, less dense chips (and more of those), some others are made from fewer high density chips. Mainboards supporting the former may, and will, fail with the latter.

This is a constantly reoccurring issue as technology moves on.

[Don_Komarechka]

I don't understand it though, it will recognize the memory configuration 16x72 (128MB) which is what these sticks are, it has support for 50ns EDO DIMMs, which these are.. everything points to proper detection...except for the idea that this is ChipKill memory.