Hardware Limits?

I've never quite understood how there can be a limit on the RAM or CPU that is installed. Is there any way to modify the laptop around the limits?

All computers' mainboards have a set limit by their design and of course their BIOS/EFI, and even more so in the case of a laptop. For example, the CPUs on MBPs are soldered into place permanently instead of using a socket, but even on boards with removable processors, they can only take so much. For another example, I have an older IWILL socket A mobo that had a 1.33ghz Athlon on it and I wanted to put in an unlocked 1800+ Athlon XP but it didn't work even though it fit physically and both CPUs had the same FSB.

Maximum recognizable RAM amounts and speeds also work similarly; putting DDR400 on a DDR266 board will work (usually, not always) but it will run at 266 speed and not 400. In the case of a laptop (once again i'll use a MBP as an example) upgrading the RAM might be limited by (once again) the BIOS/EFI; even though they make 2GB DDR2667 SODIMMS, I can't just drop a pair of them in my Core Duo (32bit) MBP since they were only designed for 2x 1GB DIMMS. This also can apply to desktop computers in many instances.

On a side note though, I did recall hearing that some older Powerbooks that were originally intended to run 640mb maximum (128mb integrated + a 512 stick I believe) were later reported to be able to run 1.12 GB (128mb + a 1GB stick) after a firmware update, but don't quote me on that.

tennis said:

I've never quite understood how there can be a limit on the RAM or CPU that is installed. Is there any way to modify the laptop around the limits?

Click to expand...

The previous poster has gone into more detail, but in simple terms the reason that laptops can be so small is that they're carefully designed around the needs of the hardware. If Apple thought you were going to put a 2.8ghz Quadcore in a MacBook, they'd have to rethink the cooling, power supply, RAM speeds and a whole host of other things.