32bit XP with 4GB RAM

[tesco]

So with this 'memory mapping' turned on do you now see more than 1.93gb in the bios?
If not then I doubt 64bit windows will do anything for you until you sort that out.

[vivitron 15]

sorry, just rereading my post, it doesn't read very well!

With "memory mapping" enabled, I see 4GB in bios. without, only 2GB.

But even with it enabled, XP (32) can only see 1.93GB

[tesco]

Well then 64bit will solve your problem.

[clocker]

Is there something specific in your board's instructions about using different colored DIMMs?
Usually, you'd expect them to be in matching slots so dual channel would be enabled.

I still think something is up with your memory...XP should be seeing over 3GB of RAM and it's apparently only reading 1 stick.
Have you confirmed that the board is set to the right memory voltage?

[vivitron 15]

This is what I'm thinking Clocker. There's something wrong somewhere along the line. I'm going to try 64 bit dual boot tomorrow, and if I can still only get 1.93, i know its either ram, or motherboard or something.

[clocker]

Sounds like a plan.

I'll predict it doesn't see 4 GB.

[lynx]

If you only see 2GB in bios then you OS isn't likely to be able to see anything extra.

I assume you have 64MB shared memory for graphics which is pulling the usable memory down by that amount.

The very fact that you can make the bios see 2GB or 4GB leads me to think that the problem lies with the bios settings, consequently the first thing I'd try is resetting those to default if you haven't already tried that.

[vivitron 15]

I've been experimenting a lot more this morning.

1. With memory mapping enabled, Bios doesnt like just 1 stick of RAM (2GB)

2. With memory mapping disabled, and 2 sticks in, bios "sees" just 2GB RAM

3. With memory mapping enabled, and 2 sticks in, bios "sees" all 4GB RAM

4. With just a single stick [stick 1](memory mapping disabled), windows 32 and windows 64 boot just fine, and see 2GB.

5. With just the other single stick [stick 2] (mem map disabled), both 32 and 64 XP boot fine and see 2GB.

A combination of 4. and 5. suggest that each RAM stick is working fine.

Coupled with 2. and 3. in order to use all 4GB in XP64, I will need to enable mem mapping.

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I tried putting the sticks of RAM in different slots, and there was no difference in any of this (suggesting that the "one black, one yellow" from a previous post was a red herring).
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6. With both sticks in, and mem mapping enabled, bios sees 4GB, XP32 sees the usual 2GB, and XP64 won't boot!

[clocker]

What motherboard and memory are you using?

[vivitron 15]

It's an Asus p5B motherboard, and 2 sticks of Corsair RAM:

Manufacturer (ID) Corsair (7F7F9E0000000000)
Size 2048 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number CM2X2048-6400C5

according to cpuz.

I have version 1803 of bios, and have just been googling if its worth upgrading.