Why cant I have 1.5GB ram?

S

SquallRealm

Limp Gawd
Joined
Nov 7, 2004
Messages
405
My computer will not allow me to have 1.5GB of RAM.

I have 4 slot Mobo. 1 of the 3 ram sticks is different.

2x CORSAIR ValueSelect 1GB (2 x 512MB) 184-Pin DDR SDRAM Unbuffered DDR 400 (PC 3200)

1x CORSAIR XMS 512MB 184-Pin DDR SDRAM Unbuffered DDR 400 (PC 3200)

Dont say its not possible because I've encountered 2 computers so far that had 2x512 sticks working in dual channel and a different 512 working alone.
 
You shouldn't mix different brands of RAM. Especially if they have different timings.
 
speakin of which, the limit is 10 lines in a sig., Yours is 12.
 
I have use Corsair memory for years and the trouble I run into is the timing. If the stock (unoverclocked) memory timing is the same you might get away with it, if their different you run into truble. I'm not saying it can't be done but I think it would probably take alot of unnessary setting. I think it has something to do with the North Bridge and how it trys to figure out what setting to use. Even if you overclock you might find one stable and the other unstable. Timing on memory is a little different than setting the voltage and fsb on a cpu.This is just my opinion. Hope it helps.
 
Mebbe I am missing something, but I thought if you run DDR you need to install them in pairs since it is a dual channel setup. You can have 1 module in 1 slot by itself and it will run in single channel mode, but after that you will need to populate the slots evenly. You can still have 1.5GBs but you would need the configuration of 2 x 512MBs and 2 x 256MBs.

From your motherboard's website for your board:

MSI Reminds You...
• Dual-channel DDR works ONLY in the 3 combinations listed in the table shown in the previous page.
• Please select the identical memory modules to install on the dual channel, and DO NOT install three memory modules on three DIMMs, or it may cause some failure.
• Always insert the memory modules into the GREEN slots first, and it is strongly recommended not to insert the memory modules into the PURPLE slots while the GREEN slots are left empty.
• This mainboard DO NOT support the memory module installed with more than 18 pieces of IC (integrated circuit).
 
Burner27 said:
Mebbe I am missing something, but I thought if you run DDR you need to install them in pairs since it is a dual channel setup. You can have 1 module in 1 slot by itself and it will run in single channel mode, but after that you will need to populate the slots evenly. You can still have 1.5GBs but you would need the configuration of 2 x 512MBs and 2 x 256MBs.

From your motherboard's website for your board:

MSI Reminds You...
• Dual-channel DDR works ONLY in the 3 combinations listed in the table shown in the previous page.
• Please select the identical memory modules to install on the dual channel, and DO NOT install three memory modules on three DIMMs, or it may cause some failure.
• Always insert the memory modules into the GREEN slots first, and it is strongly recommended not to insert the memory modules into the PURPLE slots while the GREEN slots are left empty.
• This mainboard DO NOT support the memory module installed with more than 18 pieces of IC (integrated circuit).
Click to expand...

SquallRealm,

What MSI says there is not so clear on some points. If you put memory only in the GREEN slots, leaving the PURPLE slots empty, dual-channel will be disabled and you will get only single-channel memory controller operation. Therefore, you should populate at least one GREEN slot before you populate a PURPLE slot in order to enable dual-channel memory controller operation. (Put it this way, if you have a matched pair of modules, put one module in a GREEN slot and then put the other module into the corresponding PURPLE slot - G1 and P1, or G2 and P2, but not G1 and P2 or G2 and P1.)

And due to memory controller limitations, most Socket 939 mainboards DO NOT support the memory modules with more than 18 pieces of IC (integrated circuit) or double-sided memory modules with fewer than 16 pieces of IC. In addition, they do not support the memory modules with IC density of 128Mbit or lower or any x4 pieces of IC (16 to 18 pieces of IC per side). This means that double-sided modules must be of the x8 configuration (with 8 or 9 pieces of IC per side); any modules which use an x16 configuration (4 pieces of IC per side) must be single-sided in order to be compatible with a Socket 939 motherboard. That also implies that the Socket 939 memory controller requires the use of memory modules with IC density of at least 256Mbit. As a result, any 128MB modules must have only four pieces of IC (x16 configuration) and be single-sided, while any 256MB modules must be single-sided in order for such modules to be compatible with Socket 939 systems.

On the other hand, virtually all 512MB and 1GB modules are of the x8 configuration, with most (though not all) 512MB modules being double-sided. As a result, most 512MB modules should not be mixed together with any 1GB modules in a Socket 939 system (due to the mixed IC densities involved); otherwise, that would increase the likelyhood of system instability and/or refusal to even boot.

By the way, what Burner27 pointed out is in red. It clearly states that you should not operate a modern dual-channel platform (except certain Socket A platforms) with three DIMM's unless you want to risk serious stability issues and/or a dead system.
 
no dual channel...i think bad things happen if you try to force dual channel with 3 sticks of ram.
 
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