K7D Master + 4GB RAM- New problem

Question

Hi this is my setup:
Dual AMD Athlon MP-A, 2133 MHz (8 x 267) 2800+ Barton A2
Motherboard Properties   
Motherboard ID   10/09/2003-AMD762-W83627-6A6S7M49C-00
Motherboard Name   MSI K7D Master (MS-6501) (bios v. 1.91- newest)
Front Side Bus Properties   
Bus Type   DEC Alpha EV6
Bus Width   64-bit
Real Clock   133 MHz (DDR)
Effective Clock   267 MHz
Bandwidth   2133 MB/s
Memory Bus Properties   
Bus Type   DDR SDRAM
Bus Width   64-bit
Real Clock   133 MHz (DDR)
Effective Clock   267 MHz
Bandwidth   2133 MB/s
Chipset Bus Properties   
Bus Type   PCI
Bus Width   32-bit
Real Clock   33 MHz
Effective Clock   33 MHz
Bandwidth   133 MB/s
My problem is that the motherbord can see only 3670016k RAM with all 4 dimms plugged
I have checked by changing setup several times that all modules and slots are working.
I addictionally checked SPD, and found that all modulles are visible as 1024.
I use Transcend TS128MDR72V6A
Memory Module Properties form (SPD)   
Module Name   Transcend TS128MDR72V6A
Serial Number   00011DA2h
Module Size   1024 MB (2 rows, 4 banks)
Module Type   Registered
Memory Type   DDR SDRAM
Memory Speed   PC2100 (133 MHz)
Module Width   72 bit
Module Voltage   SSTL 2.5
Error Detection Method   ECC
Refresh Rate   Reduced (7.8 us), Self-Refresh
Highest CAS Latency   2.5 (7.5 ns @ 133 MHz)
2nd Highest CAS Latency   2.0 (10.0 ns @ 100 MHz)
Memory Module Features   
Early RAS# Precharge   Not Supported
Auto-Precharge   Not Supported
Precharge All   Not Supported
Write1/Read Burst   Not Supported
Buffered Address/Control Inputs   Not Supported
Registered Address/Control Inputs   Supported
On-Card PLL (Clock)   Supported
Buffered DQMB Inputs   Not Supported
Registered DQMB Inputs   Not Supported
Differential Clock Input   Supported
Redundant Row Address   Not Supported
I have also foud that info from chipset is wery strange- showing some non existing 5-th memory slot.
This is the info
Chipset Properties   
Motherboard Chipset   AMD-760MPX
CAS Latency   2.5T
RAS To CAS Delay   3T
RAS Precharge   3T
RAS Active Time   6T
Memory Slots   
DRAM Slot #1   1024 MB (Registered ECC DDR SDRAM)
DRAM Slot #2   1024 MB (Registered ECC DDR SDRAM)
DRAM Slot #3   1024 MB (Registered ECC DDR SDRAM)
DRAM Slot #4   512 MB (Registered ECC DDR SDRAM)
DRAM Slot #5   256 MB (Registered ECC DDR SDRAM)   
There should be 1024 MB module indicated in slot #4 - but insted there is some s....
What can be wrong?  I'm getting mad cause This Transcend modules cost me a fortune - and i bought it cause i  really need it... all four!!!

Answer 1

This is from the Tyan mainboard web site
http://www.tyan.com/products/html/tigermpx_spec.html
* Note: The AMD-760 MPX requires a portion of memory to be reserved for PCI devices. Allocation for these devices is dependent on the number of PCI devices installed, and option ROM for each device. Common configurations will see 3.5GB to 3.8GB of available memory.
Several brands of mainboard say this unless they support more than 4GB.
MSI does not mention this on their web site or in the manual.
I suspect the only solution is to get a mainboard that supports 6GB or more.