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1. #SPECCY RAM SPEEDS FREQUENCY VS LATENCY SERIAL NUMBER#
2. #SPECCY RAM SPEEDS FREQUENCY VS LATENCY CODE#

I am using 1 stick of 4GB RAM, currently it is on single channel but I will get later second 4GB RAM stick so I run them in dual channel. Width of bank 1 ECC/parity SDRAM devices.Cpu-z: and imgur: the simple image sharer Interface voltage level of this assembly (not the same as V cc supply voltage) (0–5) Mostly, parameter ranges are rescaled to accommodate higher speeds. The DDR DIMM SPD format is an extension of the SDR SDRAM format. Stored little-endian, trailing zero-padded Minimum row active–row active delay (t RRD) Bank 2 may be same width, or 2× width if bit 7 is set. Width of bank 1 ECC/parity SDRAM devices. Interface voltage level of this assembly (not the same as V cc supply voltage) (0–4)ĭIMM configuration type (0–2): non-ECC, parity, ECC First comes the highest CAS latency (fastest clock), then two lower CAS latencies with progressively lower clock speeds. The SPD ROM defines up to three DRAM timings, for three CAS latencies specified by set bits in byte 18. A most significant nibble of 0 is reserved to represent "undefined". In such cases, the encodings for 1, 2 and 3 are instead used to encode 16, 17 and 18. The most significant nibble can contain values from 10 to 15, and in some cases extends higher. Most values specified are in binary-coded decimal form. The first SPD specification was issued by JEDEC and tightened up by Intel as part of its PC100 memory specification. Memory device on an SDRAM module, containing SPD data (red circled) PPD used a separate pin for each bit of information, which meant that only the speed and density of the memory module could be stored because of the limited space for pins. īefore SPD, memory chips were spotted with parallel presence detect (PPD). Note that the semantics of slot-id is different for write-protection operations: for them they can be not passed by the SA pins at all. With a final R/W bit it forms the 8-bit Device Select Code.

#SPECCY RAM SPEEDS FREQUENCY VS LATENCY CODE#

All those values are seven-bit I☬ addresses formed by a Device Type Identifier Code prefix (DTIC) with SA0-2: to read (1100) from slot 3, one uses 110 0011 = 0x33. SPD EEPROMs also respond to I☬ addresses 0x30–0x37 if they have not been write protected, and an extension (TSE series) uses addresses 0x18–0x1F to access an optional on-chip temperature sensor. Not only can the communication lines be shared among 8 memory modules, the same SMBus is commonly used on motherboards for system health monitoring tasks such as reading power supply voltages, CPU temperatures, and fan speeds. The EEPROM shares ground pins with the RAM, has its own power pin, and has three additional pins (SA0–2) to identify the slot, which are used to assign the EEPROM a unique address in the range 0x50–0x57. This reduces the number of communication pins on the module to just two: a clock signal and a data signal.

The SPD EEPROM firmware is accessed using SMBus, a variant of the I☬ protocol. For example, the SPD data on an SDRAM module might provide information about the CAS latency so the system can set this correctly without user intervention. Devices utilizing the memory automatically determine key parameters of the module by reading this information.

#SPECCY RAM SPEEDS FREQUENCY VS LATENCY SERIAL NUMBER#

These bytes contain timing parameters, manufacturer, serial number and other useful information about the module.

In most cases, there is a special optional procedure for accessing BIOS parameters, to view and potentially make changes in settings. Some computers adapt to hardware changes completely automatically. SPD is a memory hardware feature that makes it possible for the computer to know what memory is present, and what memory timings to use to access the memory. Since about the mid-1990s, this process includes automatically configuring the hardware currently present. When an ordinary modern computer is turned on, it starts by doing a power-on self-test (POST). Earlier 72-pin SIMMs included five pins that provided five bits of parallel presence detect (PPD) data, but the 168-pin DIMM standard changed to a serial presence detect to encode much more information. In computing, serial presence detect ( SPD) is a standardized way to automatically access information about a memory module. Standardized way to automatically access information about a memory module