Originally Posted by Retrofan
("My A1200 gets unstable and freezes/ reboots from time to time...
...It can boot into workbench but sometimes it just freezes...")
Freezes with expansions (and gurus during bootup) are most commonly due to bus signal loss between CPU and motherboard, either due to bad contact or mis-timing. (Sometimes these become apparent at transfer from ROM bootstrap code to IDE initiation when fastmem is being used at its higher speed, but what IDE unit is at the end matters not.) On rare occasions freezes are caused by the CPU shutting down or failing because of high temperatures, but such temperatures are of course easily detected.
I trust Kingston, Lexar and Sandisk to be reliable - Sandisk up to but not including the Extreme IV series.