64-bit OS but only 2GB Useable?

[Ease]

Just went through an ordeal to install Windows 7 today (had an Upgrade Key, so had to install XP first!) and now I've found that I can only access 2GB of my 4GB of RAM!

Anyone know a solution?

 

[Ease]

I've just looked through the entire BIOS and didn't see anything that seemed relevant. The motherboard states that it can take up to 4GB, with 1GB in each slot (which is what I have done).

Edit: Just got this from CPU-Z; look at the Timings for slot 2. Yet I get no errors on Memtest or Windows Memory Diagnostics?

Memory SPD
-------------------------------------------------------------------------

DIMM # 1
SMBus address 0x50
Memory type DDR3
Module format UDIMM
Manufacturer (ID) Sharp (B000000000000000)
Size 1024 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number OCZ3G13331G
Serial number 12D02424
Manufacturing date Week 24/Year 02
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 5.0-5-5-14-19 @ 370 MHz
JEDEC #2 6.0-6-6-16-22 @ 444 MHz
JEDEC #3 7.0-7-7-19-26 @ 518 MHz
JEDEC #4 8.0-8-8-22-30 @ 592 MHz
JEDEC #5 9.0-9-9-24-33 @ 666 MHz

DIMM # 2
SMBus address 0x51
Memory type DDR3
Module format UDIMM
Manufacturer (ID) OCZ (7F7F7F7FB0000000)
Size 1024 MBytes
Max bandwidth PC3-8500F (533 MHz)
Part number OCZ3G16001G
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no

DIMM # 3
SMBus address 0x52
Memory type DDR3
Module format UDIMM
Manufacturer (ID) OCZ (7F7F7F7FB0000000)
Size 1024 MBytes
Max bandwidth PC3-10700H (667 MHz)
Part number OCZ3313331G
Serial number 12D00024
Manufacturing date Week 24/Year 07
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 5.0-5-5-14-19 @ 370 MHz
JEDEC #2 6.0-6-6-16-22 @ 444 MHz
JEDEC #3 7.0-7-7-19-26 @ 518 MHz
JEDEC #4 8.0-8-8-22-30 @ 592 MHz
JEDEC #5 9.0-9-9-24-33 @ 666 MHz

DIMM # 4
SMBus address 0x53
Memory type DDR3
Module format UDIMM
Manufacturer (ID) OCZ (7F7F7F7FB0000000)
Size 1024 MBytes
Max bandwidth PC3-8500F (533 MHz)
Part number OOZ3G166011
Number of banks 8
Nominal Voltage 1.50 Volts
EPP no
XMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 5.0-5-5-12-19 @ 380 MHz
JEDEC #2 6.0-6-6-14-23 @ 457 MHz
JEDEC #3 7.0-7-7-16-27 @ 533 MHz
JEDEC #4 8.0-8-8-19-31 @ 609 MHz

 

[Ease]

64-bit OS yet only 2GB usable?

More info here: http://forums.overclockers.co.uk/showthread.php?t=18137361
But as I now think it's probably not just Windows messing around I'm going to try here instead!

I have two pairs of RAM, both from OCZ, but of different speeds. They both worked fine on my old mobo until I killed it with some incredibly unlucky overclocking (Q6600 to 2.8GHz if you'll believe it... so unlucky!). However, I'm having some curious problems on my new motherboard (EP41T-UD3L).

With the 1066MHz pair in slot 1 and 3, and the 1600MHz pair in slot 2 and 4, the machine recognises all 4GB but says (in Windows) only 2GB usable with 2GB reserved for hardware.

With the pairs the other way around it POSTs, and then crashes a split second before the Windows start up.

With just the 1600MHz in, in slot 1 (or 1 and 3) it POSTs fine, shows some weird artefacts in the top left hand corner of the screen before start up for about 20 seconds, then starts up fine. Then in Windows it recognises 2GB of the RAM, and all of it is usable.

With just the 1066MHz pair in it boots and starts up fine.

I also noticed that my motherboard has some stickers on saying "DDR3 1333MHZ!!!" yet no mention of acceptable memory speeds in the manual. What solutions can you suggest? Thank you in advance, for any advice you may proffer.

 

[Ease]

I suspect this is Memory at fault, rather than Windows, so have moved the topic:
http://forums.overclockers.co.uk/showthread.php?t=18137525

 

[Ease]

But with the current 1600MHz on its own I get the weird start up?

Also, I just saw this footnote on GIGABYTE's site:

* Because of Intel chipset limitation, please use single-side memory module if four memory modules are to be installed.

How can you tell if they are single-sided or not?

 

[Ease]

I thought that as well, but saw on Tom's Hardware:

It doesn't have anything to do with where the chips are mounted. Double-sided modules have two sections and the motherboards that support them have memory controllers that switch between the "sides" of the same module and can only access one side at a time.

Ah, and just saw on GIGABYTE's "acceptable memory list" that one pair of mine is single sided and the other is double sided (despite looking the same! ). I suspect that is my problem then.

http://www.gigabyte.com.tw/FileList/MemorySupport/mb_memory_ga-ep41t-ud3l.pdf

I've seen that my motherboard supports this Geil 4Gb Pair, so might buy that instead, unless someone can recommend a better 4Gb pair that is on the list?

http://www.overclockers.co.uk/showproduct.php?prodid=MY-086-GL&groupid=701&catid=8&subcat=1516

 

[Ease]

Ah sorry, didn't see your edit. I don't have a Memory Remapping feature in my BIOS, or anything that looks even slightly relevant; I've checked a few times, sure that I must've been overlooking it but I'm now absolutely certain it isn't there.

 

[Ease]

Sorry, didn't know! Will do in future!