Because you bought an HP

I hate dealing with the likes of HP and Dell - they cut corners in strange places! OK, from what I can find, it looks like some versions of your board (Which is an HP-only oddity) may only be able to support PC2100 RAM, (which is very f**king strange as it's a S478 board?!) however, the HP site claims it can handle the PC-2700 stuff as well. Does it work as expected if you just have the single stick of new RAM in there?

Try running this program from Crucial -

User Posted Link

It should tell you what you can upgrade to.

As an aside, even the PC-2100 stuff should be able to run at a Bus speed of 133MHz, instead of 100MHz. The PC-2700 on its own can do 166MHz, but if you try that with mis-matched RAM it'll s**t itself. Which could be why it has gone back to default (100MHz).

Use matching speeds only and let me know how you get on

Posted By: Iwan Husarmi, Jan 15, 18:33:47