PE SC430 won't boot with 4GB memory

I have a Poweredge SC430 that is running Windows XP Pro SP2 (32bit). I have just upgraded the memory to the following:

Kingston 4GB (4 x 1GB) 240-Pin DDR2 SDRAM DDR2 667 (PC2 5300) ECC Unbuffered Dual Channel Kit Server Memory Model KVR667D2E5K2/2G

 

When I try and boot, it just gets stuck on the Dell logo screen (can't get into the bios settings though). I have tried both pairs of memory sticks separately and have tried them in different memory banks. They work at 2GB just not if I try all 4.

 

I have the latest Dell BIOS.

 

I have tested with 4 sticks of 512mb memory for a total of 2GB. It works just fine.

 

I ran some tests on the memory pairs separately. No errors. I flashed the BIOS, no change. Very strange. Dunno what else to try. Do you think it could be the HIS Hightech H155HMF256EL1N-R Radeon X1550 256MB 64-bit GDDR2 PCI Express x1 Low Profile Video Card, that I have installed? Maybe because of the shared memory issue?

 

What I have tried so far:

 

1. Pulled ATI X1550 Hypermemory video card.
2. Using on board video, I booted in fine, then just as all services have finished starting up, the system freezes.
3. Shut down (pull power, ouch)
4. Started up
5. Go into BIOS
6. Turn off something called SERR DMI message (I think), as it said, "Some video cards require that SERR DMI be turned off".
7. Would not boot still. Got an Uncorrectable Memory Error at blahblahblah
8. Pulled ATI 1550 and put it into the PCIe X8 slot.
9. Booted in just fine, freezes after services are done loading.
10. Replaced ATI 1550 with an old PCI 256MB Radeon 9250
11. Booted in just fine, freezes after services are done loading.
12. Ordered 4 x 1GB DDr2 PC 4200 ECC memory from Newegg. Tried it. No difference.

 

Any help would be appreciated. I would like to have both the x1550 video card and the 4GB of memory working.

 

 

 

****************Problem Solved*********************************************

 

Ok, so finally I've gotten somewhere. I have a PCI-e X1 usb/firewire card that was plugged into the X8 slot to make room for the video card. I pulled that out. I put the video card into the X8 slot, I put the usb/firewire card into the X1 slot. Before doing this, I had booted into the BIOS and turned that SERR DMI message back to on. I turned everything off, put all for sticks of ram back in and booted. It's been on now for about half an hour and it works. I'm very happy. Although I still don't know why it wasn't working with the video card in the X1 slot. Thanks for all the suggestions. Unfortunately, if I had kept the faster memory, I have a feeling it would've worked in this configuration. Final config looks like below. I've been trying to get this thing going so that I can begin transferring and editing all of the video I've shot of my kids.

PowerEdge SC430
XP Pro (soon to be Vista Ultimate x64)
Pentium D 840 (3.2GHz)
4GB PC-4200 DDR2
HIS PCI-e x1 radeon X1550 256mb(512mb Hypermemory)
TV Wonder 650 Pro TV Tuner
2x80GB 7200rpm sata2 (hardware raid SIIG II PCI)
1x250GB 7200rpm sata2
1x1TB 7200rpm sata2
22inch Hanns-G widescreen lcd monitor

Using Adobe Master Collection CS3  to edit all the photos and videos.