Yes. I ordered a 1600+ that would not post in the 2 of my machines that supported XP's officialy. I thought it might be a memory problem or something, so I ordered a 1800+ just to see if that one would post. ( I sent an e-mail to newegg, and told them waht I as doing so I did not go over the RMA period ) The 1800+ posted just fine, so I sent back the 1600+
I had to pay shipping back to them, but they next day air'd out the replacement after "processing" which took 6 days ( including a weekend )
Does that help? Feel free to PM me If you have a specific question.