T2130CT - laptop batteries memory

What is SDRAM? SDRAM is an acronym for Synchronous Dynamic Random Access Memory. The term "Synchronous" means that the clock cycle of the memory is exactly synchronized with the clock cycle of the bus. Every calculation and operation a PC performs is timed according to a clock ticking millions of times each second, its clock cycle or megahertz rating. If the memory clock cycle is not in sync with the bus clock cycle, system problems will occur. What is Cache Memory? Cache, pronounced "cash", is a high-speed memory designed to supply the processor with the most frequently requested data and instructions. The information located in the cache memory can be accessed many times faster than information in the system''s main memory. The more information your system can retrieve from the cache memory, the more efficient the system will run. Level 1 (L1) cache, also referred to as Primary Cache, is normally located inside the CPU chip. Level 2 (L2) cache, also referred to as Secondary Cache, was normally located on the system board near the CPU in the past. In today''s systems, both are physically located within the CPU and as a result are not upgradable.

What is the difference between 2-clock and 4-clock memory? Two types of SDRAM modules are the 2-clock and the 4-clock module. Structurally, they are the same, but they are accessed differently. A 2-clock SDRAM module is set up so that each clock cycle accesses two chips on the module. A 4-clock SDRAM setup accesses 4 chips per clock cycle. To choose what kind to get, you must look into the motherboard''s documentation. 4-clock modules are the more commonly used. The typical indication of the wrong type being used is a system giving error beeps and not booting as it cannot use the memory installed. The system will not proceed past POST (Power On Self Test). 2-clock was only used in 66 MHz systems. All PC 100 and PC 133 memory is 4-clock only. Do all of your SDRAM modules use SPD? SPD, or Serial Presence Detect, is a program in an EEPROM chip on the modules of SDRAM (Synchronous Dynamic Random Access Memory). It tells the system’s BIOS what the specifications and settings of the memory module are. All of our SDRAM DIMMs have SPD programming. The system BIOS should therefore be set on AutoDetection for memory.

You can think of RAM as an incredibly fast hard drive that stores information temporarily instead of permanently. When you start a program it is loaded from the hard drive into RAM. When a program is running in RAM it can run hundreds to thousands of times faster than it can if run directly from the hard drive. The problem is that the capacity of a standard hard drive is many times the size of a computer''s RAM size, meaning it is possible to load so many programs that the RAM can no longer hold them. When that happens, your computer''s virtual memory kicks in, and that''s bad. Virtual memory is simply your hard drive trying to act like a RAM chip. Since the hard drive is so much slower than real memory, programs stutter and sometimes crash when the hard drive has to do a job it was never designed for. There are only two solutions to this problem: close some programs until virtual memory is no longer needed, or add more physical memory. If you can afford it (and current memory prices are low enough that practically anyone should be able to), the latter solution is always preferable.