I purchased one of these back in October to upgrade my notebook from 512mb to 1gb of Ram. I the item worked flawlessly. I decided to purchase a second one in March to upgrade to 2gb. Unfortunately, the two chips would not work together even though they were the same specification. (This chip is the one that Kingston recommends for my Gateway MX6439).
I contacted Kingston's tech support, who did a thorough investigation into the problem. They had me send the defective chip back to them (paid for the shipping), and replaced it with a new one which has worked without problems since.
I can't say enough about Kingston's tech support! They are the best, and should be the example that all other companies should strive for with their tech support department. I never waited on hold more than a minute or two, and through this process I dealt with a gentleman named Juan who gave me his personal phone number and email address to contact him while we were in the process of diagnosing the problem!
Even though I had some problems with the item, I will not hesitate to purchase Kingston products again in the future!