How to Remove Lag/Hang from Windows 7 When upgrading RAM greater than 8 GB on HP ProBook 4540s (16 GB)

This is a workaround that worked for me.

It is not an official or supported solution.

I have used the laptop extensively in described configuration and did not have issues that i can relate to memory configuration.

Deducing 256 MB RAM from memory available to OS might eliminate the problem for some CPUs.

The solution works on:

- HP 4540s

- i5-2450M

- AMD/Intel switchable graphics

- 16 GB RAM

- Bios F.42

It might work for other CPUs.

Under Windows you should deduce 256 MB RAM, by using EasyBCD or similar tool.

Instructions for EasyBCD:

Under Advanced Settings/Developer set 256 under "MiB deducted from physical memory", save settings and restart.

Under Linux, set "mem=17G" in kernel boot parameters (effectively deduces 256 MB).

Edit:

Under Windows 7 and later, you may also use the following instead of EasyBCD:

bcdedit /set {current} removememory 256

(Execute the command in command prompt with administrative privileges and reboot).

http://h30434.www3.hp.com/t5/Desktop-Boot-and-Lockup/Performance-degrades-in-Probook-4540s-after-memory-upgrade/td-p/2268503