(Updated with content from: What exactly is the cause of RAM incompatibility?)
I have changed memory modules in computers since 1992, but this is a puzzle I have not managed to crack: Why does a
NT2GC64B8HCONS-BE work in a Lenovo T410, but these will not:
When I boot the machine, it very shortly crashes after boot. The machine is known to support 2x4GB RAM, and all 4 tested modules are known good (they work in other systems flawlessly).
I thought it might be a voltage problem, but:
So that is not the problem. Also 1.35V should be backwards compatible according to this thread.
https://superuser.com/a/1252970/41337 is a pretty good resource, but it does not go into what features are backwards compatible and which features are not. E.g. RAM frequency will be negotiated to be the highest supported by both computer and RAM according to https://www.crucial.com/usa/en/support-memory-speeds-compatability It also does not cover how to tell what density a given DIMM has and how to tell if this is supported by the computer.
But the answer is decent template for the known features so far of
- Memory technology: DDR3
- CAS latency: ? (Isn't this part of timings below?)
- Voltage: 1.5V (1.35V is backwards compatible)
- Timings: ?
- RAM frequency: Backwards compatible (1600 MHz RAM will work with 1066 MHz controllers and vice versa)
- RAM density: This https://panoramacircle.com/2018/08/07/high-density-vs-low-density-ram-why-it-crashes-some-computers/ shows exactly the same behaviour on exactly the same machine. So this leads me to believe RAM density could be the issue. The
HMT451S6AFR8A-PBhas 8 chips and says 1Rx8, while
NT2GC64B8HCONS-BEhas 16 chips and says 2Rx8.
- RAM controller: Supports 4G DIMMs
- Chipset technology: ?
What feature does
NT2GC64B8HCONS-BE have, that the other three don’t? And how can I tell if other 4G modules will be compatible?