Search results
Results From The WOW.Com Content Network
One of the major improvements the PCI Local Bus had over other I/O architectures was its configuration mechanism. In addition to the normal memory-mapped and I/O port spaces, each device function on the bus has a configuration space, which is 256 bytes long, addressable by knowing the eight-bit PCI bus, five-bit device, and three-bit function numbers for the device (commonly referred to as the ...
The maximum random access memory (RAM) installed in any computer system is limited by hardware, software and economic factors. The hardware may have a limited number of address bus bits, limited by the processor package or design of the system. Some of the address space may be shared between RAM, peripherals, and read-only memory.
A memory rank is a set of DRAM chips connected to the same chip select, which are therefore accessed simultaneously. In practice all DRAM chips share all of the other command and control signals, and only the chip select pins for each rank are separate (the data pins are shared across ranks).
Memory transactions between 64-bit devices may use all 64 bits to double the data transfer rate. Non-memory transactions (including configuration and I/O space accesses) may not use the 64-bit extension. During a 64-bit burst, burst addressing works just as in a 32-bit transfer, but the address is incremented twice per data phase.
Earlier DIMM generations featured only a single channel and one CA (Command/Address) bus controlling the whole memory module with its 64 (for non-ECC) or 72 (for ECC) data lines. Both subchannels on a DDR5 DIMM each have their own CA bus, controlling 32 bits for non-ECC memory and either 36 or 40 data lines for ECC memory, resulting in a total ...
DDR4 memory is supplied in 288-pin dual in-line memory modules (DIMMs), similar in size to 240-pin DDR3 DIMMs. DDR4 RAM modules feature pins that are spaced more closely at 0.85 mm compared to the 1.0 mm spacing in DDR3, allowing for a higher pin density within the same standard DIMM length of 133.35 mm (5¼ inches).
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
For example, the Intel Westmere 5600 series of processors access memory using interleaving, wherein memory access is distributed across three channels. If two memory DIMMs are used per channel, there is a reduction of maximum memory bandwidth for this configuration with UDIMM by some 5% in comparison to RDIMM. [2] [3]