H/W reserved is 50% of my physical RAM

Asus P7p55d deluxe motherboard
October 7, 2010 at 15:20:08
Specs: Microsoft Windows 7 Home Premium, 2.891 GHz / 2045 MB
I see this is a common problem in Win7, but I have also not found any solution.

Wondering if this has to be resolved on a case-by-case basis?

Windows 7 reports 4096 physical installed, but according the resource monitor the H/W reserve is 2051MB. Summary (MB): Installed = 4096, Total = 2045, Cached = 778 and Available = 766

The msconfig advanced boot options has all the boxes unchecked and it didn't make a difference when I tried to explicitly configure the max mem either.

From CPU-Z:

Chipset
-------------------------------------------------------------------------

Northbridge Intel DMI Host Bridge rev. 11
Southbridge Intel P55 rev. 05
Graphic Interface PCI-Express
PCI-E Link Width x16
PCI-E Max Link Width x16
Memory Type DDR3
Memory Size 4096 MBytes
Channels Dual
Memory Frequency 803.3 MHz (2:10)
CAS# latency (CL) 8.0
RAS# to CAS# delay (tRCD) 8
RAS# Precharge (tRP) 8
Cycle Time (tRAS) 24
Row Refresh Cycle Time (tRFC) 89
Command Rate (CR) 2T
Uncore Frequency 2570.6 MHz

DIMM # 1
SMBus address 0x50
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Corsair (7F7F9E0000000000)
Size 2048 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number CMD4GX3M2A1600C8
Manufacturing date Week 20/Year 09
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.2
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-23 @ 444 MHz
JEDEC #2 8.0-8-8-22-30 @ 592 MHz
JEDEC #3 9.0-9-9-24-34 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.650 Volts
Min Cycle time 1.250 ns (800 MHz)
Min tRP 10.00 ns
Min tRCD 10.00 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 50.63 ns
Min tRFC 110.00 ns
Min tRTP 7.50 ns
Min tRRD 7.50 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-31-2T @ 600 MHz (1.650 Volts)
XMP #2 8.0-8-8-24-41-2T @ 800 MHz (1.650 Volts)

DIMM # 2
SMBus address 0x52
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Corsair (7F7F9E0000000000)
Size 2048 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number CMD4GX3M2A1600C8
Manufacturing date Week 20/Year 09
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP yes
XMP revision 1.2
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 6.0-6-6-16-23 @ 444 MHz
JEDEC #2 8.0-8-8-22-30 @ 592 MHz
JEDEC #3 9.0-9-9-24-34 @ 666 MHz
XMP profile XMP-1600
Specification PC3-12800
Voltage level 1.650 Volts
Min Cycle time 1.250 ns (800 MHz)
Min tRP 10.00 ns
Min tRCD 10.00 ns
Min tWR 15.00 ns
Min tRAS 30.00 ns
Min tRC 50.63 ns
Min tRFC 110.00 ns
Min tRTP 7.50 ns
Min tRRD 7.50 ns
Command Rate 2T
XMP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
XMP #1 6.0-6-6-18-31-2T @ 600 MHz (1.650 Volts)
XMP #2 8.0-8-8-24-41-2T @ 800 MHz (1.650 Volts)


See More: H/W reserved is 50% of my physical RAM

Report •

#1
October 7, 2010 at 18:45:32
Could it be you're running the 32-bit version of Win7?

Why doesn't my Windows® PC recognize the whole 4GB of memory I installed?


Report •

#2
October 7, 2010 at 19:11:17
Nope definitely Windows 7 64 bit. I know the system will reserve a certain amount, but 50% seems excessive.

According to the system function of the control panel:

Installed Memory (RAM): 4.00GB (2.00 GB usable)
System Type: 64-bit Operating System


Report •

#3
October 7, 2010 at 22:03:01
I saw this on the MS support knowledge base:

"If you’re using a 64-bit version of Windows and see a difference between the amount of installed memory and the amount of usable memory, you might need to change some settings in your computer’s basic input/output system (BIOS). For more information, check with your computer manufacturer."

I went through the Asus BIOS and manual for the P7P55D Deluxe and I don't see any setting that would affect this. Doesn't mean that the memory configuration parameter is *not* in the BIOS settings - I saw nothing that looked like it would change the memory configuration. The onboard HDA is disabled in the BIOS.

I also found this:

Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

"This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine. "

However, I can't tell which device(s) or chip(s) would be reserving 2GB of memory - no onboard video support for the P7P55D, right?


Report •

Related Solutions

#4
October 7, 2010 at 22:19:23
This is from msinfo32:

OS Name Microsoft Windows 7 Home Premium
Version 6.1.7600 Build 7600
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Name VOODOOCHILD
System Manufacturer System manufacturer
System Model System Product Name
System Type x64-based PC
Processor Intel(R) Core(TM) i5 CPU 760 @ 2.80GHz, 2891 Mhz, 4 Core(s), 4 Logical Processor(s)
BIOS Version/Date American Megatrends Inc. 1807, 7/22/2010
SMBIOS Version 2.6
Windows Directory C:\Windows
System Directory C:\Windows\system32
Boot Device \Device\HarddiskVolume1
Locale United States
Hardware Abstraction Layer Version = "6.1.7600.16385"
User Name VoodooChild\Not Sure
Time Zone Pacific Daylight Time
Installed Physical Memory (RAM) 4.00 GB
Total Physical Memory 2.00 GB
Available Physical Memory 897 MB
Total Virtual Memory 3.99 GB
Available Virtual Memory 2.68 GB
Page File Space 2.00 GB
Page File C:\pagefile.sys

and the I/O memory resources start here:

0x00000000-0x0000000F Direct memory access controller OK
and end here:

0x0000FFE0-0x0000FFFF Intel(R) 5 Series/3400 Series Chipset Family SMBus Controller - 3B30 OK

Thats only 64K


Report •

#5
October 7, 2010 at 22:45:56
Asus and Intel have looked into this problem. Asus links to a 2005 Intel white paper that discusses memory re-mapping. I have the Memory Remap Feature = enabled

Intel chipset memory supprt

2. Windows 64-bit OS which can address more than 4GB memory.

Asus memory allocation

So can it be that this main board is just a huge memory hog and you need 6GB RAM to yield 4GB usable?


Report •

#6
October 8, 2010 at 07:24:03
Same problem reported on Asus P7P55D Deluxe message board, still no resolution.

P7P55D Deluxe message board

I read that the system reserves RAM for the video card = to the amount of RAM on the card.

Is this true??? SO I give up 1GB system RAM, right off the top, for the GTS 450?

I thought that's why video cards have RAM - so you don't have to give up your system physical RAM.


Report •

Ask Question