##notes
I've tried a few things. 
booting with different flags (ie acpi=off / noacpi / sync)
bios settings : 
Plug and Play(irqs) enable/disable
I've disabled all unused ports (parralel/gameport/media port etc)
I've tried installing the sata drivers directly into the kernel. But I haven't
succeeded in compiling a ubuntu kernel. But from my understanding modules will work with initramfs 
which is the defacto with ubuntu xen-server meta package.

##info
uname -a
Linux li64 2.6.24-16-generic #1 SMP Thu Apr 10 12:47:45 UTC 2008 x86_64 GNU/Linux

##OS
Ubuntu Hardy Beta
##Xen Installation method: 
Using Xen meta package apt-get install xen-server


##hangs here on boot. and repeats until eventually it loads into shell (initramfs)
ata3: Sata link up 1.5Gbps (SStatus 113 SControl 300)
ata3: timeout waiting for ADMA Legacy clear and IDLE

##Grub
title           Xen 3.2 / Ubuntu 8.04, kernel 2.6.24-16-xen
root            (hd0,0)
kernel          /xen-3.2.gz
module          /vmlinuz-2.6.24-16-xen root=/dev/mapper/lvmvolume-root ro console=tty0
module          /initrd.img-2.6.24-16-xen
quiet

##CPU INFO
cat /proc/cpuinfo 
processor	: 0
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 35
model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
stepping	: 2
cpu MHz		: 2500.001
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 2
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow rep_good pni lahf_lm cmp_legacy
bogomips	: 5003.10
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp

processor	: 1
vendor_id	: AuthenticAMD
cpu family	: 15
model		: 35
model name	: AMD Athlon(tm) 64 X2 Dual Core Processor 3800+
stepping	: 2
cpu MHz		: 2500.001
cache size	: 512 KB
physical id	: 0
siblings	: 2
core id		: 1
cpu cores	: 2
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow rep_good pni lahf_lm cmp_legacy
bogomips	: 5000.06
TLB size	: 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp

##LSPCI
lspci
00:00.0 Memory controller: nVidia Corporation CK804 Memory Controller (rev a3)
00:01.0 ISA bridge: nVidia Corporation CK804 ISA Bridge (rev f3)
00:01.1 SMBus: nVidia Corporation CK804 SMBus (rev a2)
00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
00:06.0 IDE interface: nVidia Corporation CK804 IDE (rev f2)
00:07.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:08.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:09.0 PCI bridge: nVidia Corporation CK804 PCI Bridge (rev f2)
00:0a.0 Bridge: nVidia Corporation CK804 Ethernet Controller (rev f3)
00:0b.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0c.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0d.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0e.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:00.0 VGA compatible controller: nVidia Corporation NV43 [GeForce 6600 GT] (rev a2)
05:06.0 FireWire (IEEE 1394): NEC Corporation uPD72874 IEEE1394 OHCI 1.1 3-port PHY-Link Ctrlr (rev 01)
05:08.0 Multimedia audio controller: VIA Technologies Inc. VT1720/24 [Envy24PT/HT] PCI Multi-Channel Audio Controller (rev 01)
05:0c.0 Ethernet controller: Marvell Technology Group Ltd. 88E8001 Gigabit Ethernet Controller (rev 13)