Dell XPS SDRAM Issues

Dell XPS710 did clean install of Windows 7 x64 from XP. All went well and things worked fine for a while. Decided I wanted to get more out of my x64 machine so decided to upgrade the RAM from 4x1GB to the system max 4x2GB. I originally ordered the wrong RAM (PC2-6400 800Mhz) and when I installed them the system wouldn't even turn on.

Picked up the correct PC2-5300 667Mhz 4x2GB units and after a clean install I put 2x2GB SDRAMs in with 2x1GB original SDRAMS. Machine shows 6.0 GB installed and lists them as 667Mhz and Dual Asymmetric. Everything works fine.

If I installed 4x2GB SDRAMs, the system says 8GB installed but lists them as 800MHz and Dual INTERLEAVED? Won't make it thru startup. Will try to do a repair but nothing works. Go back to 6 or 4 GB and things are fine?

Any ideas?

TIA - Stretch

You probably weren't using the 4GB RAM you had to being with. So adding to make it 8GB is a fairly pointless exercise and will not give any noticeable benefit to the machine.

Adjust your bios settings for memory Vdimm (voltage) and timings. Check the Ram maker's page about your specific modules and adjust accordingly for all Ram settings.

After a marathon Dell Tech Support chat session last night, they claim the issue is a BIOS upgrade. Prior to upgrading to Windows 7 I was told by Dell Tech Support to upgrade my Bios in order to turn on Virtualiztion if I wanted to use the XP mode in Windows 7. I did that and upgraded to Bios 1.4.1 and turned on Virtualization. I didn't end up downloading the XP Emulator or whatever it is that Windows 7 offers but that bios flash apparently is causing the issues. I will be getting a new motherboard and have been advised that I should NOT have upgraded the BIOS.

Until then, I'm able to use 2x1GB + 2x2GB for 6GB of Ram and things are running fine. The jump from 4GB to 8GB isn't fairly pointess considering I usually have most of Adobe's Creative Suite, iTunes & Outlook open simultaneously and regularly deal with large graphics files. I guess I'm willing to do the research in hopes of some noticeable benefits. I do notice that the quad core processor is rarely above 20% whereas the 4GB of RAM was regularly upwards of 75%+ according to the CPU Meter Gadget.

Thanks for the tip, the vdimm and timing is something I've never heard of or checked so it'll be a good starting point.

Thanks-Stretch

Update: New Motherboard installed and still unable to run 8GB of RAM. If I run 4GB or 6GB all is fine. As soon as I run the full 8GB, the memory shows up as 800MHz rather than the 667Mhz it actually is and I start getting the random instant restarts. No BSOD, just instant and random restarts. I've taken the system back to it's most basic form, no wireless keyboard/mouse, no USB external drives installed, no wacom drawing monitor, just the CPU, basic monitor and keyboard. Dell says it's a driver of some sort but I've updated everything and still get the random crashes!?!?!?! HELP!

Thanks-Stretch