Well, in 3 weeks of testing 3 different 512Mb PC2700 sticks - all of them Samsung 'DTL' based, I found that my current Samsung Original 512Mb PC2700 'DTL' stick is doing DDR400 quite easily. The first 2 sticks were bad. First one was a Samsung on 3rd and the 2nd stick was a used stick that
www.overclockers.co.uk sold to me (I'm still annoyed about that as they don't want to give me a refund! Selfish people.) Both of those sticks just about did DDR375.
Anyway, the 3rd and current stick, a Samsung Original 'DTL' stick too, is actually a replacement stick that
www.MicroDirect.co.uk sent me because they gave me a Samsung on 3rd, meaning Samsung chips on a 3rd party supplier's PCB, hence not always a good memory stick for overclocking. I RMA'd that stick back to them and they sent me the Original one this time and WOW it sure is a good stick. Easily doing DDR400 with 2.7v vdimm on my ABIT BG7 running at 160MHz FSB.
By the way, the Samsung chips on my current stick are dated Week 0217, if that helps.