You reduce the amount of additional memory that can added without replacing the 1st module. Eg. 3 slots and 2 64's gives a possible addition of a 128 : 64+64+128=256
3 slots, 1 128 leaves room for 2 128s: 128 + 128 + 128 = 384
With the first setup you have only 256MB, second 384MB; which would you prefer?
The disadvantage is that you've almost halved the total amount of RAM you can have in your system. Assuming your system only support up to 128 MB modules, you can now only have a total of 256 MB of RAM, instead of 384. If your computer supports 256 MB modules, you could have supported 768 MB, instead of 384 MB.
Primarily, restriction of future expandability; with two 512MB sticks in a three-slot main board, you will only have one slot remaining for future upgrades. This would mean having to buy a higher capacity, more expensive stick of RAM rather than two smaller ones, or settling for only a 50% increase with a matching stick. It might also make overclocks less stable (for advanced users), requiring looser RAM timings where a single stick might be more stable at higher clock speeds.
There is no disadvantage other than you are using up slots that you might want to use later for upgrading.
As the memory speed is limited, you essentially double the available speed by having two modules, as they run in parallel. The efficiency is generally increased by 20-30% by having two 512mb modules rather than one 1GB module.
None, other than the fact that you are taking up motherboard slots for future upgrades.
DIMM- DUAL INLINE MEMORY MODULE RIMM - RAMBUS INLINE MEMORY MODULE SIMM SINGLE INLINE MEMORY MODULE
The only advantage I can think of is the situation when one of modules fails and still have another one to work with.
Ram bus Inline Memory Module
SODIMMs(Small Dual Inline Memory Modules)
DIMM stands for dual inline memory module
Advantage : In HIPO chart all input and output for each modules are clearly identified and also determine very easily that what modules call the modules being examined. Disadvantage : The main disadvantage of HIPO is that the documentations for a program gets to be rather bulky: there is a page for each module regardless of the actual size of the module.
ECC stands for Error Checking and Correction. This type of memory module is used to correct memory errors within the computer registry. ECC memory modules generally have 9 chips compared to 8 chips in a non-ECC memory module. This is the easiest way to differentiate the two.
1. DIMM modules are open standard. SIMM modules are copyrighted standard.
There are a number of different names. They are usually in the form of SIMMs (Single Inline Memory Modules), and people often call them just memory modules. Some also call them memory cards or memory sticks. They may go by other names based on the exact chips and how they are wired, such as DDR, DDR2, DDR3, and so on.They are sometimes called MultiChip Modules. When their sole function is RAM they can be called Memory Modules.Sometimes they are identified by the type of connector: SIMM, DIMM, UDIMM, SODIMM, etc.Memory Modules (memory card)