Need ideas about RTAS memory

Here's the issue, and I'm hoping some can help, because it doesn't make sense. I had a Dell Precision T5500. It died and the Dell "certified" guys in my area couldn't solve why. I looked at the Avid site for weeks and bought an HP Z600. Operating System Windows 7 Professional with SP1, HP Factory Recovery Disks included

Processors Available TWO of Intel Xeon® SIX-Core Processor X5650(12M Cache, 2.66 GHz, 6.40 GT/s)

Chipset Intel® 5520(Dual)

Form Factor Rackable MiniTower

Memory

Memory Tri-channel 24GB DDR3 ECC PC10600 1333GHz

Memory Slots 6 DIMM slots up to 48GB

Storage

Drive Bays Internal Drive Bays:

2 internal 3.5" bays (up to 3 with converter)

External Drive Bays:

2 external 5.25" bays

Hard Disk Controller Integrated SATA with RAID 0, 1, 10, 5 support

Hard Drive Brand New 1T SATA HDD+120G SSD

Optical Drives DVD+/-RW with LightScribe

Audio, Slots, and Ports

Audio High Definition Integrated Realtek ALC262 Audio

Slots 2 PCI Express Gen2 x16, 1 PCI Express Gen2(x8 mechanica l/ x4electrical)

1 PCI Express Gen1(x8 mechanical/x4 electrical)

2 PCI

Ports Front:

3 USB 2.0,1 microphone in,1 headphone

Rear:

6 USB 2.0

2 PS/2

1 audio in

1 audio out

1 microphone in

1 RJ-45 to integrated Gigabit LAN

Pro Tools 8, Mbox 2 Pro (I have a Focusrite Sappire 56 in waiting)

So I figured it to run even better, but it was crashing with the typical "error" messages.

Here's the issue. For instance, One session on the Dell had over 66 plugins.

It plays fine.

Another session recorded on this HP has only 16 plugins and it's giving errors.

I've "optimized" 7, etc. But this new PC should handle this much easier. Any Ideas?