What Is SPD in CPU-Z?
The CPU-Z utility displays detailed information about the memory modules installed in a computer using a feature called Serial Presence Detect. The "SPD" tab in CPU-Z displays this information, helping you learn more about the computer's configuration and confirm that memory module makes and models are as expected.
The "SPD" tab in CPU-Z displays the size, maximum speed, manufacturer, model number and production date of each memory module in the computer. CPU-Z also detects whether a module is registered, buffered or error-correcting. The bottom half of the window displays the latency timings that a memory module is compatible with at all supported speeds.
The memory in your computer is capable of running faster than its current speed, allowing you to upgrade the processor to one with a faster bus speed without buying new memory. For example, DDR2-400 can run at 266, 333 or 400 MHz. However, unless you assembled the computer yourself, you may not know the memory module speed options unless you opened the computer and examined them. The "SPD" tab in CPU-Z enables you to see this information without opening your computer.
Manufacturer and Model
Manufacturers often make "budget" and "premium" versions of their memory modules. While a high-end memory module may cost significantly more than a budget module, the performance difference between the two is often so small that a typical user wouldn't detect it without running a benchmark test. Therefore, an unscrupulous computer builder may buy low-cost memory modules, modify them to look like premium modules and resell them at a profit. The "SPD" tab in CPU-Z displays the actual manufacturer and model of your computer's memory modules, assuring you that they are genuine.
CPU-Z also displays an overview of the hardware installed in a computer. In addition to the computer's memory, CPU-Z displays the brand, model and speed of the processor, the manufacturer, model and chipset of the motherboard and the manufacturer and model of the video adapter.