I have a Toshiba Satellite L505d-s5965 that I've had for about 2 years. The 3gb standard memory just didn't seem like it was hacking it so I picked up 2x4gb sticks that I dropped in. I've upgraded the OS to Windows 7 Ultimate, so 8gbs shouldn't be a problem, right? System won't boot with both 4gb sticks in, however if I throw in one 4gb stick and the old 2gb stick, it boots up no problem. I've checked and flashed the BIOS, there's no options under BIOS for memory so I'm not sure what it is. Any suggestions?
p.s. When I put both 4gb sticks in and enter the BIOS, it reads the full 8192, so...someone please help!
laptops are notoriously picky about Ram. Many of them have ridiculously low limits on what they will accept, and if the timings are off just a little then they will not post. My bet is that the ram you bought is 1) too much (check manufacture's website for Max Ram supported), or 2) just off enough from the expecting timings that is dosn't want to play nicely. Find the system specs on the original stick of ram and try to match it as close as possible. It has to have the same MHz rating, as well as timings (typicality 9,9,9,24 or something similar for DDR3)
Win 7 Ultimate (the same as Pro by the way, you may want to try to get some money back on that) 64bit will do 4GB or more, the 32bit version will not, and that is true for home and pro versions as well.