Tweet
I have an ancient Macbook Pro 5,1 from 2008 that I decided to test just for fun. I don't recall ever having crashes or problems with it, but it's failing tests in a strange way and I'm thinking it might be a false positive. I've read and googled over the forums and noticed a number of other reports of bugs in Apple's UEFI in that era, so maybe this is one of them.
This laptop has 8GB of RAM made of 2 SODIMMs. This model originally only officially supported 4GB of RAM but everyone knew you could put 8GB in and it would run fine. In the last official UEFI update Apple made the 8GB support official, but nothing really changed as far as I can tell.
The modules are two Mushkin 976644A. The module chips are labeled 256x8ddr3 with a date code of 1208. http://www.poweredbymushkin.com/Home...ry/646-976644a
The Memtest used was the latest, 9.4 b1000.
Here's what happens:
The memory region in question is approximately 0x158000000 to 0x15f000000, about 5.5GB in. I've never seen errors outside of this range.
On the first pass after boot errors will be found in tests 7 and 9. I've never seen other error types.
No pass other than the first pass will ever find errors. I've run up to 12 additional passes multiple times and errors are never found after that first pass.
The number of errors is fairly small. It's always 10-30 each time.
Normally it takes 9 hours for a full 4-pass test to complete, but if I focus the test to the address range above and skip tests 10 and 13, it only takes a few minutes. I ran at least six full 9-hour tests and dozens of range tests.
Testing the modules individually in each slot finds no errors. Swapping the modules does not cause the address range to move.
This laptop has 8GB of RAM made of 2 SODIMMs. This model originally only officially supported 4GB of RAM but everyone knew you could put 8GB in and it would run fine. In the last official UEFI update Apple made the 8GB support official, but nothing really changed as far as I can tell.
The modules are two Mushkin 976644A. The module chips are labeled 256x8ddr3 with a date code of 1208. http://www.poweredbymushkin.com/Home...ry/646-976644a
The Memtest used was the latest, 9.4 b1000.
Here's what happens:
The memory region in question is approximately 0x158000000 to 0x15f000000, about 5.5GB in. I've never seen errors outside of this range.
On the first pass after boot errors will be found in tests 7 and 9. I've never seen other error types.
No pass other than the first pass will ever find errors. I've run up to 12 additional passes multiple times and errors are never found after that first pass.
The number of errors is fairly small. It's always 10-30 each time.
Normally it takes 9 hours for a full 4-pass test to complete, but if I focus the test to the address range above and skip tests 10 and 13, it only takes a few minutes. I ran at least six full 9-hour tests and dozens of range tests.
Testing the modules individually in each slot finds no errors. Swapping the modules does not cause the address range to move.
Comment