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Only 3GB Usable and Slowing Down my System (64-bit OS)

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Hello, everyone. This is my first post on the Tom's Hardware forum, but I've been coming to the site for years.

I'm having a problem with my Abit IP-95 and reading the correct amount of ram and its slowing down my system.


Cliff Notes:
1. New (2x 2GB) ram install only shows 3gb of ram in XP 32-bit & Win7 64-bit.
2. I'm positive this ram is slowing down my system.
3. Memtest reveals no errors
4. I have the latest bios on my motherboard, which actually addresses amount of ram issue. (but obviously didn't help me)

More details below

I decided to upgrade from 2GB (2 x1GB) to 4GB of ram (2x 2GB) when I was running XP 32-bit, knowing I would only be able to see around 3gb. Around that time i started to notice my system would run really choppy and tasks such as multiple tabs in Firefox would jump my CPU usage to 100% constantly. When i just had the original 2GB sticks installed everything was fine. I ram Memtest and it found no errors in my new ram.

Well i was hoping when i upgrade to Windows 7 Home Premium (64-bit) all my issues would go away. The first problem i noticed is that in system properties it says my installed memory was, "4.00gb (3.00gb usable)" I was almost set on just ignoring this when I decided to play Left 4 Dead and my system ran it horribly. (choppy, jumping around, sound issues) This was just like when my XP install would run very slow after i installed the new ram. I removed one stick leaving one stick of 2gb installed, reran Left 4 Dead and it ran perfectly, better than ever.

I'm convinced my new install of ram is slowing down my system.

Also I looked up any issues with my motherboard and it supports 4gb of DDR2 ram and there was a bios update that should have solved my issue. and my CMOS has been reset after the installs of OS and RAM.

Any suggestions? Is it possible to reinstall a bios update? my mobo only supports DDR2 533, but the ram is DDR2 800, could that be a factor?

Thank you,


My system specs:
Windows 7 64-bit retail
Motherboard: Abit IP-95 Bios v.13
Intel Core 2 Duo 2.53
4GB G.SKILL (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)

More about : 3gb usable slowing system bit

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Memory Authority

On older boards, there is an option somewhere in the BIOS to enable memory remapping. (software, if you have the choice...some boards will allow you to enable hardware and software remapping, you are looking for software if you have both choices in the menus)
You have to turn this before anything above 3 gig will be addressed.
One way to confirm this, check the memory count at POST, it will only count to 3 gig if this is the problem and solution.

Mongox said:
Haven't done the 7 thing myself, but this should still be available.

In MSConfig - Boot.ini - Advanced Options. Make sure nothing in MaxMem


That setting is for debugging purposes only and doesn't affect the operating system.
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Thanks for the replies. Actually I've read on memory remapping and checked to see if its an option in my bios and its not. Also, 4gb is shown in my memory count at post.

My motherboard is rather old, but i was hoping to not have to build another computer in a year or so.
Memory Expert

This chipset does not support memory remapping so you'll never be able to use all 4GB, even with 64-bit OS. Its a hard limit of the chipset.

Quote:
That setting is for debugging purposes only and doesn't affect the operating system.

Ehhh...that setting only affects the operating system. You can try it yourself. Place a check mark in the box and set the maximum memory to 4GB. It will limit the OS to 4GB max.
Memory Authority

Yes, changing the MaxMem may be for debugging, but that doesn't prevent it from limiting the OS memory. We've solved several problems like this after finding a setting there.

Thanks tcsenter. Seems like there's boards so old that they don't have the re-mapping, then older ones that have it, then newer ones that don't even bother with it again.

Manual has no info on BIOS - simply shows the main screen and you're on your own.

This motherboard has a strange DRAM slot configuration. It has 2 DDR slots and 2 DDR2 slots! Seen something like that mentioned before but hadn't run across it.

Mongox said:
Seems like there's boards so old that they don't have the re-mapping, then older ones that have it, then newer ones that don't even bother with it again.


All newer boards support it. Some boards just enable it by default without making it an option.
Memory Authority

yep yep, that's what I meant. I don't think anyone ever needs it set the other way anymore - no boards sold to support Win95 or OS/2 anymore.

Just like few boards use RAM this big!
Memory Expert

Mongox said:
This motherboard has a strange DRAM slot configuration. It has 2 DDR slots and 2 DDR2 slots! Seen something like that mentioned before but hadn't run across it.

ABIT IP-95 is just a rebranded ECS P4M890T-M2 with better capacitors. ABIT used a number of ECS boards on the value end. A lot of companies do, though they may not simply rebrand an ECS model like this.

Quote:
All newer boards support it.

Well except the ones that don't. e.g. Intel 945GC, Intel G31/P31, et. al.

There might of course be some exceptions and then it depends on how you define "newer". G31/P31 supports memory remapping very well.

If I should add a bit. 945GC only supports 4GB address space, so a remapping function would be rather pointless.
Memory Expert

mikrev007 said:
If I should add a bit. 945GC only supports 4GB address space, so a remapping function would be rather pointless.

As it is on G31/P31, which has the same hard limit as i945.

From the specs:

The (G)MCH supports 64 GB (36 bit) of host address space

The reclaim base/reclaim limit registers remap logical accesses bound for addresses above 4 GB onto physical addresses that fall within DRAM.
Memory Authority

Mongox said:


This motherboard has a strange DRAM slot configuration. It has 2 DDR slots and 2 DDR2 slots! Seen something like that mentioned before but hadn't run across it.


Well, that could be the problem right there. There was a period when a few boards were "transistional" during the DDR to DDR2 phase. They had slots for both types of memory. HOWEVER, they will only work correctly with 1 type installed. You cannot install and mix both types at the same time!
Late edit, but after rereading, this does not appear to be the problem with the OP's system as he is only running 2 sticks of memory.

what the exact amount of ram it shows in the post? cause i am sure its not saying its 3GB even. it might be reserving some of the ram for other devices on the board.

but it could be a design limitation of the board anyway because the specs say it only supports a max of 4GB but maybe it only supports like 3.5GB.
Memory Expert

mikrev007 said:
From the specs:

The (G)MCH supports 64 GB (36 bit) of host address space

That's processor address space. The Northbridge can only decode a maximum 4GB DRAM:

- Using 1 Gb device technologies, the largest memory capacity possible is 4 GB,
assuming Dual Channel Mode with two x8 double sided un-buffered non-ECC
DIMM memory configuration

- The (G)MCH supports a maximum of 4 GB of DRAM. No DRAM memory will be accessible above 4 GB.


tcsenter said:
That's processor address space. The Northbridge can only decode a maximum 4GB DRAM:

- Using 1 Gb device technologies, the largest memory capacity possible is 4 GB,
assuming Dual Channel Mode with two x8 double sided un-buffered non-ECC
DIMM memory configuration

- The (G)MCH supports a maximum of 4 GB of DRAM. No DRAM memory will be accessible above 4 GB.


I was quoting the chipset specs. Yes, the chipset only supports 4GB RAM, but the address space is larger than that. There is a difference between RAM and address space.

Have you not read the specs? There are several pages explaining its memory remap feature. 945G has a 32bit interface to the CPU, P31 has a 36bit interface.

Lets take a board as an example: P5KPL-VM
If you go to bios setup, you will find a memory remap function right there.

Thanks everyone for the detailed answers. I appreciate all your help.

Does anyone know if this cap on my memory could be causing a slowdown in my system even when running games that aren't super system intensive?

I'm thinking about selling the two 2gb sticks and just keeping my two 1gb sticks for another year. I would keep the 4gb if i didnt feel like they were slowing down my system.
Memory Authority

It seems from the discussion above that the roadblock in you being able to use more than 3GBs of RAM isn't due to the OS being 32-bit or 64-bit, but to the design of most boards using this chipset.

Adding RAM that works properly will never slow down your system. Your system should run faster and better in Win7 than in Vista - but that's just a guess. But no idea if it'll run better in Win7 64-bit, for which it was clearly not designed, or in Vista 32-bit. The best OS might be Win7 32-bit for you.

So there's no reason that having 4GBs (3GB) in your system will actually run slower than 2GBs. It should run Vista faster with the 4GBs - even if it only addresses 3GBs.

Again, I don't think having the memory is slowing down your system. I'd stick with the Vista and save the Win7 64-bit for your new hardware. Of course, if you can sell or return the 4GBs of RAM now it will fund a portion of an upgrade to a newer MB, RAM and CPU - any money spent on old hardware is basically down the drain at all times unless it makes a visible improvement in your system now.

Memory Expert

mikrev007 said:
Lets take a board as an example: P5KPL-VM
If you go to bios setup, you will find a memory remap function right there.

I'll have to take your word for it. The last 10 persons with a G31/P31 based mobo that I've seen posting inquiries about why their system addressed less than ~3.5GB RAM with 64-bit OS did not have any setting for memory remapping in their BIOS.


Quote:
Does anyone know if this cap on my memory could be causing a slowdown in my system even when running games that aren't super system intensive?

Its not the chipset memory limit that would cause the slowdown. But a buggy BIOS that wasn't properly setting-up things like MTRR settings when 4GB is populated sure could. Seen it before.

tcsenter said:
I'll have to take your word for it.


You don't need to take my word for it. You can just download the manual for the board and check the bios section.

And most important, the chipset specs has it covered.

I Goolged my problem and found this thread. I'm having the same problem as the original poster. There are few differences. After I switched from 32bit Vista to 64bit Windows 7, I added 2 more Corsair XMS2 sticks to the 2 I already had. The 2 new memory sticks are a couple of years newer and look different even though they are the same specs. But with them installed my system is quirky. Sometimes everything runs smoothly and other times everything runs extremely slow and clunky. I removed the 2 newer ram chips and the system runs great. My system is a Gateway GM5424 that I purchased March of 2007. I changed many of the components. My system setup now is:

Intel (Stoughton) G965 Motherboard
Intel Core 2 Duo E6700 Processor
Corsair Twin2X2048-6400C4 memory
Antec Truepower Trio 650w Ver. 2.2
BFG GeForce 8800GT OC

Could it be that the newer ram chips are not compatible with the older pair or is it the motherboard can't handle the 4megs.
Memory Authority

alpha, give us the part number for the newer RAM - and the specs. Not sure if you went from 2GBs to xGBs. If you can list the part numbers of the older RAM also, plz do so. Most important on the old RAM is what voltage is listed on them physically.

I think your problem is different since you have a newer board and it's unlikely that is doesn't support more than 3GBs. Is this a Gateway computer? That's the only listing I found under the name Stoughton. If you know it, plz post the URL with the specs on motherboard.

Quote:
alpha, give us the part number for the newer RAM - and the specs.


Thank you very much for the reply. It may not be necessary now but here are the specs:

CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail.
5-5-5-15 2.1v

Both the first and second pair are identical. I purchased both sets from Amazon about 2 years apart. I didn't get the second set until after I switched from Windows Vista 32 bit to Windows 7 64bit. I know that you wouldn't get the full advantage of 4gb on a 32bit setup so I didn't bother with getting 4gb until I installed Windows 7. Anyway after I posted here I found someone with the same problem on another forum. It was suggested that they increase the size of their paging file. I tried that and also put the paging file on a second hard drive. All have been well for the few days since. I'm surprised it was such a simple solution, if it holds up. I was sure it was some sort of hardware conflict. Thanks again and take care.

~eddie

What video card are you using? The video card memory takes away from user memory space. It's probably reserving 1GB for system components and video memory. On a 32-bit OS this is not remotely uncommon.
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