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RAM Stuck At 448mb?
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Post by
Ghulag
/me thinks mileron may be right, given that your scan thingo also says your MB can only support a max of 1 gig. switch back a 1 gig chip and see what happens.
Post by
309394
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Post by
Wanderingfox
The site linked above says "maximum memory 2GB".
It doesn't say "2GB per slot/chip"
It says "2GB".
So the MB is probably freaking out when it sees the 2GB chip since it doesn't know what to do with it and just reports 512MB.
If you put a 1GB chip in there you'll have no problem.
The FSB shouldn't care where the chips are on the bus so long as they're there. If that is in fact the issue, it should be correctable with a simple BIOS update.
Post by
Deveritas
Since his motherboard can only support 1gig of ram, how would the 2 gig stick work?
Would the gig just essentially throttle itself down to 1 stick?
Also, some people were confused about the 448 MB displaying about the 512mb stick. His ram is sharing Video Memory, which 64+448=512 mb.
Post by
321294
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Post by
309394
This post was from a user who has deleted their account.
Post by
321294
This post was from a user who has deleted their account.
Post by
Wanderingfox
A 2GB stick will not work properly if the motherboard has been designed for a maximum of 1GB per stick - it's that simple. One indication that this is the case is that the motherboard cannot be upgraded beyond 2GB, and it has 2 RAM slots.
Last I checked (which, i admit, was a few years ago when I got my A+) the memory restrictions of a motherboard were limited by the bios and the CPU/operating system running. The bus shouldn't care what's being given to it since all it does is handle traffic. Perhaps it's something specific in regards to 2gig+ sticks that I just know about?
Post by
309394
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Post by
321294
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Post by
Wanderingfox
If the motherboard does not have the circuit board traces etched into it that are required to access more than 1 GB, it won't - no matter what the BIOS or Operating System tells it to do. The fact that it can access only 256MB of each side of the 2GB stick (resulting in the 512MB that was seen) tells me that it doesn't have the necessary electrical connections run to the memory slots in order to utilize a 2GB stick.
But that doesn't explain the issue. If it was unable to access all of the chips on the RAM then it would only be able to get 512mb off each slot, which puts the max of the mobo to 1gig total. The motherboard specs state 2gig max which would imply that it should be able to get at least a gig off each slot, but it clearly isn't. Also, the traces on the motherboard have absolutely no impact on maximum capacity, just throughput (assuming we're talking purely about DIMM RAM here, which I am since SIMMs went out of fashion decades ago).
Finally, ram isn't designed like that. ALL RAM will have either 4, 8, or 9 memory banks on them (the chips). This is because each one is x megabits (2x megabits in the case of 4 chips) of the x megabyte memory stick (the ninth bank would be for an error checking bit). For your theory to be correct, you'd be implying that the computer can't physically access 3/4ths of EACH memory bank on the stick, which doesn't make sense. It's more than likely a limitation with the memory controller itself or with the BIOS.
Post by
309394
This post was from a user who has deleted their account.
Post by
Wanderingfox
Multiple reasons:
The revision of the BIOS firmware that is currently running on his motherboard does not address memory past 512mb (This would explain why the 512 stick works fine, and why he can only access the first 512mb of the 2gig stick).
The memory controller is faulty and unable to address memory address past 0x200.
The 2gig stick itself is faulty and misreporting the size of the chips on the board.
It could be an older 2gig stick that's actually 2 1gig sticks on a single board (ie. 16 memory banks piggybacked into 8 groups of 2), but that would only reduce the performance of the ram to 1gig.
He could have the 512 stick in one slot, and the 2gig in the other, which could cause the mobo to attempt to use dual channel mode and limit the 2gig stick down to 512.
The BIOS could be manually set to dual channel mode (either by a setting in the BIOS or a jumper on the motherboard) and be expecting even amounts of ram in both slots (coupled with the possibility of a memory addressing issue could result in a limiting of the RAM).
The CPU he's using does not support addressing past a certain address (unlikely, but included for completeness since I mention the 24gig limit of DDR3 SDRAM below which is a result of addressing limitations of the core i7 and the lack of RAM with more than 2gigs per stick).
The RAM could be undervolted in the BIOS, thus physically preventing the system from reaching the higher memory addresses, but he'd likely be seeing blue screens left and right if that were the case.
The AMOUNT of memory a motherboard can handle is an arbitrary number defined by the maximum RAM size at the time the motherboard was created (baring a few limitations, none of which would limit a 2gig to 512. If it were limited to 1gig, it would make more sense). Guessing based on the age of his mobo, I'd guess that it came out just before/after 1gig single sticks came on the market. Thus the BIOS was designed to handle 512, and later updated via a firmware update to handle the 1gig sticks, and they never bothered to update the firmware to handle 2gig sticks.
Explain to me how a motherboard with 6 DDR3 SDRAM slots can only use 3 gigs of ram on a 32bit OS? (even though I could put 6 2gig DDR3 SDRAM sticks in there)
The answer: It doesn't care how much is there, it's a BIOS/OS/CPU limitation. For example, Windows XP (x86) uses a 32bit address scheme which means it's limited to 2^32 memory addresses, or 4,294,967,296 bytes, which is about 3.25 gigabytes. Windows XP (x64) uses 64bit addressing and can thus handle 2^62 memory addresses (~ 16 exabytes).
This same principal effects the BIOS as well. If the firmware running does not support addressing past a certain memory limit then it will simply fail to see memory past that limit.
Like I said, it's been several years since I got my A+ cert, so maybe things have changed, or I'm simply not remembering correctly, but your theory does not fit with the way ram functions (at least it doesn't to my knowledge anyway).
Not trying to start an argument, I'm just genuinely curious as to why it's happening. It's an unusual issue.
Post by
309394
This post was from a user who has deleted their account.
Post by
Wanderingfox
The problem with that theory, again, is that if it can only address 256 per bank, then there's no way to reach the advertised 2gig max. Though I will admit that that theory is currently the most likely :/
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