Some machines get quite fussy about this stuff.
That's where Crucial is nice.......they do the homework.
Two sticks of ram at the same speed/type/voltage can be quite different in their innards.
So I'm playing around with this old boat anchor I had out in my garage and came across a problem I have never seen before. The unit is a HP Pavilion a1328x, has an ASUS P5RC-LA mobo, pentium 4 3.06 GHz, and the factory installed 512MB ddr2 pc4200 240 pin DIMM. Chipset is ATI Radeon Xpress 200 for Intel Processors, and bios is phenox-award.
Some back ground, this thing was bricked got it at a yard sale for 5 bucks a while back, ended up being the hard drive, so I purchased a 500Gig to replace the 80 factory jobber, installed, then loaded a fresh copy of xp professional sp3, everything worked. I went over to the HP site and re-downloaded and updated all drivers, now running version 3.08 in the bios. Everything works great. I decide I want to install more ram, go to crucial site enter info and got that I needed 2 x 1GB DDR2 PC5300 Un buffered, no ecc. I go to best buy and pick up som PNY ram in the correct configuration, put on my trusty ground strap and install.
Here is the problem:
Power it up and no bios no os, just constant steady beeping and a black screen, also the cooling fan for the cpu is turning a billion rpm like its overheating. I immediatly shut it off, discharge power, remove one of the two new sticks, restart, and same result... I remove the new ram and re-install the factory one, starts up no issue.
Also I tested the new ram on another junker I had lying around, was an old dell, the ram works on that one. I have never seen this before.