Optiplex 780 leds 1 e 3 piscando

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Below is what the Diagnostic LED's 1 and 3 represent on your computer.

Memory modules are detected, but a memory configuration or compatibility error has occurred.

Ensure that no special requirements for memory module/connector placement exist. Ensure that the memory you are using is supported by your computer.

What Is DDR3 Memory?

DDR3 continues the evolution in memory technology and provides several improvements to the exsisting DDR2 architecture. The primary benefit is an increase of the I/O bus to operate at 4 times the speed of the memory cell it contains. DDR3 also allows for chip capacities from 512 MB to 8 GB. This ability in effect allows for memory modules of up to 16 GB in size.

Memory Configuration

DDR memory can run in dual-channel mode, which allows the system to have twice the memory bandwidth using the same memory technology.

Dual-Channel Configurations

To achieve dual-channel performance, the total memory in each channel must be the same. If the channels do not match or if the system has only one DIMM installed, the system memory operates in single-channel mode or in dual channel asymetrical mode. The system works normally in single-channel mode, but the user loses the benefit of increased memory throughput.

Dual-channel mode is always present when both memory channels are populated. However, for optimum dual-channel performance, the size of the modules must match.

Basically, when both DIMM connectors are populated, the system has optimum dual-channel performance unless channels A and B have different amounts of memory.

Memory Speeds

Some confusion has been created due to the difference in the actual listings for speed ("MHz") and the way memory is described from a sales standpoint ("PC XXXXXX"). The listings below should resolve any confusion.

Troubleshooting

Memory errors on the system display the new ON-FLASH-FLASH or ON-FLASH-ON failure code. If all memory fails, the LCD does not turn on. Troubleshoot for possible memory failure by trying known good memory modules in the memory connectors on the bottom of the system as well as under the keyboard. As always, follow the instructions in DSN and perform all steps suggested to verify the problem. 4 GB Memory Barrier The Windows® XP release as well as 32-bit versions of Windows Vista can only use a maximum of 4 GB of address space. However, the amount of memory available to the operating system is less than 4 GB. Certain components within the computer require memory address space in the 4 GB range. Any memory address space reserved for these components cannot be used by the operating system.

NOTE: This is a limitation of a 32-bit architecture: the system can only address 4 GB of allocated memory. Allocated memory is made up of physical RAM and any I/O space needed by devices. Normally this is not a problem, but when a system has 4 GB of physical memory, the memory addresses needed to map RAM overlap the space needed for the I/O devices. In this case the need for I/O space takes precedence, and the amount of RAM visible to the operating system is limited to 4 GB minus the I/O allocation.

More information on the limitation of 32-bit addressing can be found in the Technical Assistance Bulletin (TA1075698) titled "Systems with 4GB of Memory Show Less Memory in Windows."

Testing Memory

The easiest way to check for memory problems is to run the Dell PSA+ Diagnostics which include a very robust memory test. If the system does not have PSA+ diagnostics or they are not available, then the MpMemory Test (included with the latest version of Dell 32-bit Diagnostics) is the best testing method.

Quando não liga pode ser memória ou processador com sujeira ou mau encaixado

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