[SOLVED] HP Pavilion ZD8000 BIOS RAM Limit?

[LoneCrusader]

Hello,

I have several HP Pavilion ZD8000 laptops. I had been using them with 2GB of RAM installed and previously was under the impression that only 2GB of RAM was supported by this particular model (2x1GB modules).

Recently I discovered that Kingston had actually issued some model-specific 2GB memory modules for this machine (KTH-ZD8000C6/2G; made sense, it is DDR2 and should support 2GB modules) and I purchased some of these.

I upgraded one of the machines to 4GB of RAM only to find that the machine will still only report 2.5GB of RAM under Windows. Looking in the BIOS revealed that the system memory listed was only "2560 MB." What gives? I know that some MMIO addressing space above 3.5GB (or at worst 3.0GB) will be lost, but a cutoff at 2.5GB seems rather random and odd.

Any way to fix this?

Link to the last official BIOS:
F.34
Thanks!


PS - I posted this in the Phoenix section because the installer for the last official BIOS is Phoenix-branded. If this is in the wrong place, please move it for me.

EDIT:
Solved for laptops using the M24 BIOS. Anyone using the M22 BIOS should post here for further assistance.
Patched BIOS attached. READ the entire thread before attempting to use.

[DeathBringer]

Make and post screenshots of first (CPU) & third (Mainboard) tabs of CPU-Z.
Make CPU-Z TXT Report and post a fragment from it beginning with "Description Host Bridge" ending with next "Description ".

[LoneCrusader]

Make and post screenshots of first (CPU) & third (Mainboard) tabs of CPU-Z.
Make CPU-Z TXT Report and post a fragment from it beginning with "Description Host Bridge" ending with next "Description ".

Code:

PCI Devices
-------------------------------------------------------------------------

Description Host Bridge
Location bus 0 (0x00), device 0 (0x00), function 0 (0x00)
Common header
Vendor ID 0x8086
Model ID 0x2580
Revision ID 0x04
PI 0x00
SubClass 0x00
BaseClass 0x06
Cache Line 0x00
Latency 0x00
Header 0x00
PCI header
Subvendor ID 0x103C
Subsystem ID 0x3082
Int. Line 0x00
Int. Pin 0x00
PCI capability
Caps class Vendor Dependant
Caps offset 0xE0
PCI registers
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
00 86 80 80 25 06 01 90 20 04 00 00 06 00 00 00 00
10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20 00 00 00 00 00 00 00 00 00 00 00 00 3C 10 82 30
30 00 00 00 00 E0 00 00 00 00 00 00 00 00 00 00 00
40 00 90 D1 FE 00 40 D1 FE 00 00 00 E0 00 80 D1 FE
50 00 00 02 00 03 00 00 B8 00 00 00 00 00 00 00 00
60 00 30 D1 FE 00 00 00 00 00 00 00 00 00 00 00 00
70 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90 10 11 11 01 31 10 11 00 00 00 00 00 A0 0A 79 00
A0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
B0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
C0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
D0 00 00 00 00 00 00 00 00 00 00 00 00 40 01 00 00
E0 09 00 09 21 42 B3 9B 88 02 00 00 00 00 00 00 00
F0 00 00 00 00 00 00 00 00 00 00 05 00 00 00 00 00

[DeathBringer]

This chipset can't use addresses higher then 0xA0000000 for operating memory. So 2560 Mb is the maximum. It can't be increased by BIOS patch.

[LoneCrusader]

This chipset can't use addresses higher then 0xA0000000 for operating memory. So 2560 Mb is the maximum. It can't be increased by BIOS patch.

Ugh, doesn't sound too promising for any solution then.

Thanks for your help though!

[LoneCrusader]

This chipset can't use addresses higher then 0xA0000000 for operating memory. So 2560 Mb is the maximum. It can't be increased by BIOS patch.

I did some further research on this and I found several links discussing other laptops using the Mobile 915GM chipset. A link back to the Intel specs for that chipset (now requires the Wayback Machine to see) does indeed state that the 915GM chipset is limited to 2GB and 533MHz FSB.

However the ZD8000 does not use the 915GM chipset, it uses the 915P/915G chipset and uses a desktop class processor rather than a Mobile one (I believe they were supposedly prone to overheating due to this but I haven't seen it with mine). Note the i915P\i915G chipset and ~800MHz FSB listed in the CPU-Z report. Links to the 915P and 915G chipset specs.

I would think this would mean that 4GB should still possible... any thoughts?

[DeathBringer]

Read Intel® 915G/915GV/915GL/915P/915PL/910GL Express Chipset (Datasheet):

32-bit host bus addressing for access to 4 GB of memory space

So all internal devices has addresses under 4Gb.
To view how your laptop has assigned I/O addresses: open Device Manager, click View at the top of the Device Manager window, click Resources by type, and then select Input/Output (IO). This should give you an output similar to the picture shown below

Resize such window to show all information. Make and post a screenshot of it.

[LoneCrusader]

Read Intel® 915G/915GV/915GL/915P/915PL/910GL Express Chipset (Datasheet):

32-bit host bus addressing for access to 4 GB of memory space

So all internal devices has addresses under 4Gb.
To view how your laptop has assigned I/O addresses: open Device Manager, click View at the top of the Device Manager window, click Resources by type, and then select Input/Output (IO)...
Resize such window to show all information. Make and post a screenshot of it.

I expected to see memory top out somewhere between 3.0 and 3.5GB; that's obviously a given with 32-bit systems. But with a cutoff at 2.5GB a lot of memory is getting wasted somewhere...

[DeathBringer]

Look at your screenshot.
PCI bus use I/O addresses: from 0xA0000000 to 0xFEBFFFFF. Because of it the chipset can't use addresses higher then 0xA0000000 for operating memory.
Theoretically this range can be reduces to 0xC8000000-0xFEBFFFFF. It should increase maximum memory to 3200 Mb. But this mod very dangerous...

[LoneCrusader]

Look at your screenshot.
PCI bus use I/O addresses: from 0xA0000000 to 0xFEBFFFFF. Because of it the chipset can't use addresses higher then 0xA0000000 for operating memory.
Theoretically this range can be reduces to 0xC8000000-0xFEBFFFFF. It should increase maximum memory to 3200 Mb. But this mod very dangerous...

Interesting. This mirrors a problem I was having on a much newer desktop system where memory seemed to be missing that should not be and XP reported the range as being controlled by the PCI Bus. Possibly a similar solution would apply there but that's an issue for another time.

I'm up for making an attempt. At worst I brick one of these laptops. I will check to see if I have another one that has some other issues to experiment on rather than test on the main one.