Dell Studio 540 Memory Issue

I'm trying to understand the picky nature of a Dell Studio
540 with a M017G motherboard.

I'm trying to replace some ram that failed. I've tried using
NANYA PC2-6400 (2x1gb Sticks) and all I get is beep codes.
I believe this ram runs at 1.8 V.

When I install the one stick of Samsung PC2-6400 back, the
computer boots fine.

I've resolved myself that the ram just won't work in this board.
Dell says any DDR2-800 ram should work.

I have the opportunity to get a 2GB stick of Aeneon 2G DDR2-667 240PIN AET860UD00-30D-P PC5300U-555 2GB DDR2-667CL2.5.

I realize this is slower ram, but I'm wondering why it wouldn't work.
BTW, I booted the same computer on a Kingston 667 chip (512)
sucessfully.

I've read through all I can find on Dell's support site, and there seems
to be no approved list of ram for this model.

Can anyone help?

Ha! I was right about the ram then! Well, I wouldn't worry too much about the DDR 667 ram, as that frequency ram is pretty old hat nowadays, meaning the quality of the stuff is usually up to par to run on Dell equipment, but if you really want no-hassle memory, look no further than Micron for a nice stick of ram. Whenever I've had boards that were picky on memory (a Dell GX50 with it's 810e chipset comes to mind), I've found Micron memory to be quite compatible. They don't make whiz-bang high performance ram, but they do make dependable, highly compatible memory modules. I'm using two Micron DDR667 512MB sticks on this Sempron LE-1100 rig I'm using to type this message right now.

Good luck

PS: I take it you used the Q6600 to test out if the Pentium D was the issue, or did you just put in the Samsung ram right away (in other words, did the Pentium D work in the Studio PC)?

KEITHAPPLE, I WOULD FIRST LIKE TO TELL YOU I HAVE A STUDIO 540 W/MO17G MOTHERBOARD/8GB@800MHZ/SAMSUNG PC2-6400 STICKS/INTEL CORE 2 DUO QUAD Q9300/2.5@1333/FSB/EVERYTHING I JUST DESCRIBED WAS OUT OF THE BOX FROM DELL/ THE ONLY MOD I MADE IS I REPLACED THE STAN/Q8300@2.33/1333FSB TO THE Q9300,
I AM RESPONDING TO THIS BECAUSE I SEE THAT HAVE SOME IMFO THAT IS NOT CORRECT THIS MOBO CAN RUN UP TO 1333MHZ NOT A MAX OF 1066,
IN REGARDS TO THE RAM ISSUE THE REASON YOU HAD A PROBLEM IS BECAUSE THE THE RAM YOU TRIED TO UPGRADE WITH DOSN'T HAVE THE SAME CL, AS THE STICKS YOU PURCHASED PC2-6400 YES BUT THE SAMSUNG HAS 666=4.0/5.0/6.0, WHAT YOU WERE PUTING IN WAS 555=3.0/4.0/5.0, YOU ACTUALLY DOWN GRADED YOUR 800MHZ TO 667MHZ, CAN'T UNDERSTAND THE BEEPING IT STILL SHOULD HAVE WORKED JUST WONDERING WHAT WAS THE STANDARD OUT OF THE BOX SET UP OF YOUR 540, I'M THINKING YOU MAY HAVE GOT THE DUO6600 PROS.. WICH I THINK IS THE BEST FOR OC. JUST COURIOUS , YOU CAN GET THE SAMSUNGS ALL OVER THE PLACE FOR AROUND 30.00 EACH M3 78T5663RZ3-CF7 2GB@800/666
MY QHESTION TO YOU IS GPU/ MINE CAME W/ HD3450, CRAP/ I REPLACED IT W MY GPU FROM MY OLD CPU WICH IS THE HD2900
1GB DDR4, MY GPU SCORE WAS 4.2 W/HD3400 AND WITH THE SWICTH SCORE 5.9 ON THE VISTA SCORE SHEET WHAT THE HELL HOW AND WHY THE 3450 IS 2.0 AND 10.1 DIR X CAN'T FIGURE THAT ONE OUT , BUT I LOVE THIS STUDIO THIS SET UP ROCKS, IT IS LIGHTNING FAST WITH WIN 7 EVEN BETTER