Modern Mobos don't support 4x1GB memory modules?

[Merovingian]

Okay, my asus A8N-SLI Deluxe manual says,

Due to chipset resourse allocation, the system may detect less than 4GB of memory when you installed four 1GB DDR memory modules.

Apparently the MSI K8N Neo4 Platinum SLI manual reports this...

"Due to the South Bridge resource deployment, the system density will only be detected up to 3+GB (not full 4GB) when each DIMM is installed with an 1GB memory module."

Interestingly enough the $78 Asrock 939NF-4G-SATAII Mobo I got for my mom for her xmas build makes no mention of a 4GB memory limitation which perhaps is the reason for the -4G- in the model number.

Can anyone shed some light on the situation? Thank you.

 

[Wentelteefje]

Normally nForce 4 should be able to handle the 4GB... I thought the limitation lay with the processors... Before Venice and X2, that is...

 

[Merovingian]

And I thought all 64bit processors could handle 16GB of ram, hmm.

 

[Wentelteefje]

No that's not what I meant... On 32-bit hardware, the virtual address space is 4 GB and the maximum amount of physical memory ranges from 4 to 128GB. On 64-bit, the virtual address space is 16 terabytes and the maximum amount of memory ranges from 64GB to 1 terabyte...

That wasn't what I meant with limitation, I was talking about the integrated memory controller of AMD64, which wasn't that optimal on CPU's before Venice and the X2's (people had problems letting it run with 4 sticks of memory, either it wouldn't work, or it slowed down to DDR333...)

 

[Zap]

Windows XP is also limited to under 4GB. I think for now if you want an AMD system that has 4GB of real, useable RAM, you'd need to go socket 940 and Windows 2003 Server.

 

[Peter]

Myth spinning ...

Folks, the PC3200 standard is what's not allowing four DIMMs at 200 MHz. No controller limitation, physics limitation. Get over it. Stepping back to 166 MHz for two-DIMM-per-channel setups is EXACTLY what the standard demands. Newer RAM controllers just add tweaks to get closer to that goal with carefully selected equipment.

As for the 4-gigabyte address space limit in 32-bit operating systems, well yes, that's that. 2^32=4GiB. You get even less RAM mapped into that space, because the graphics card's RAM and other misc largeish stuff needs to be mapped into that 4-GiB room.

 

[firstep]

I meet the similar situation that my ECS nForce4-A939 MB doens't recognize 4x1G RAM fully. I've gone through this thread, and find there are some confusing points here.

1. The issue is about 4G RAM, or 4x1G RAM? It's different, as 4G could be 2x2G, or 1x2G + 2x1G. "Due to chipset resourse allocation, the system may detect less than 4GB of memory when you installed FOUR 1GB DDR memory modules". Here it explicitly states 4x1G, instead of 4G. But if memory address space is the reason, how come 2x2G will be OK?

2. Someone mentions PC3200 standard doesn't allow four DIMMs at 200MHz. How come?

 

[funks]

I ran 4x1GB on my EPOX 9NPA+SLI. With HW remapping on (bios option), WinXP64 saw all 4 gigs of RAM. On WinXP32, it only had 3.2 gigs (due to the 32 bit 4GB address space, some of the memory range is used for memory mapped i/o).

 

[firstep]

Hi, funks. I think you can make the XP 32-bit recognize all 4G by doing some setting called PAE. I don't know the details. But you may google.

XP 64-bit still has problems with application and drivers. So if I were you, I would stick to 32-bit version.

Originally posted by: funks
I ran 4x1GB on my EPOX 9NPA+SLI. With HW remapping on (bios option), WinXP64 saw all 4 gigs of RAM. On WinXP32, it only had 3.2 gigs (due to the 32 bit 4GB address space, some of the memory range is used for memory mapped i/o).

 

[furgussen]

Hi All. Hate to throw another question into the mix, but I have a problem with my Gigabyte 8KNXP. I had 2Gigs of DDR400 in there (4x512MB) and it worked fine at Dual Channel. Driving down the road I saw a sale on RAM and had to get more. There are 6 DIMM slots on the mobo, I've filled them up with 6x512MB, but the BIOS only see's 2GB. All 6 sticks are DIMM's, and the mobo documentation says for some reason it can't have all DIMM's, some have to be SIMM's. If they don't run at dual channel, then I'll live, but it'd be nice to actually see the 3gigs of ram.

So, has anyone run into this? Fixed it?

Tyler