The Conversion Relationship Between the hardware measuring unit and the related unit

When we purchase and use computers on a daily basis, we will inevitably encounter some hardware measurement units. Maybe you can access these units, but what do they mean? What is the Conversion Relationship between related units? What is the impact on hardware performance? I'm afraid I don't know much about it. Today, we will make a more detailed explanation and analysis on this issue. Do not miss out if you are interested!

Hz (HZ)

It is usually defined as the number of changes or vibrations of waveforms per second. The Hz definitions vary with hardware in the computer.

CPU: Hz indicates the clock frequency. The current CPU is usually measured in MHz and GHz.

Display: There are three frequency indicators in the display, namely the row Scan Frequency (row frequency), the Field Scan Frequency (also called the refresh frequency) and the bandwidth frequency. The higher the three frequency indicators, the higher the maximum resolution and refresh rate of the display.

Speaker and earphone: usually used to measure the frequency range of the speaker or earphone, such as 50Hz ~ 20000Hz (20 kHz), indicating that the speaker can play 50Hz (Low Frequency )~ Various music components between 20000Hz (high frequency.

1000 kHz/s (seconds) 1 kHz = 1000Hz

MHz 1 million times/s (seconds) 1 MHz = 1000 kHz

GHz 1 billion times/s (seconds) 1 GHz = 1000 MHz

NS (nanoseconds)

It is usually used to indicate the access speed of physical memory and video memory. The smaller the value, the higher the limit operation frequency. The relationship between the memory unit ns and the limit frequency is shown in the following table:

Memory
Fetch speed
SDRAM most memory
High operating frequency
Ddr sdram memory
Maximum operating frequency

2.8 ns
N/
714 MHz

3.3ns
N/
606 mhz

3.5ns
N/
571 mhz

3.6ns
N/
556 mhz

4ns
N/
500 mhz

4.5ns
N/
444 mhz

5ns
200 mhz
400 mhz

5.5ns
182 mhz
364 mhz

6ns
166.5 mhz
333 mhz

6.5ns
154 mhz
308 mhz

7ns
143 mhz
286 mhz

The formula for calculating the maximum operating frequency of the video memory is:

Maximum running frequency of SDRAM = 1000 running ns

Limit operating frequency of ddr sdram = (1000 running ns) × 2

Note: There is no difference between the memory chip and the memory chip, so the measurement units of the two are general.

Rpm (rpm)

It is used to indicate the number of revolutions per minute of the motor, mainly hard drive motor and cooling fan motor. For example, a hard disk can be divided into 7200rpm rpm and 5400 rpm by speed. 7200rpm is a high-speed hard disk and 5400rpm is a low-speed hard disk. Generally, the data transmission speed of a high-speed hard disk is faster than that of a low-speed hard disk.

In addition, in the fan with the same fan blade length and number of blades, the high rpm certainly has a larger air volume and better heat dissipation effect, but the noise is also relatively large.

Byte (bytes) and bit (bit)

These are two very confusing concepts, as defined in the book: 1 Byte (bytes) = 8 bits ). Byte is a storage unit, which is usually used to measure the storage capacity of storage devices such as hard disks, floppy disks, and optical disks.

1KB = 1024 bytes

1 MB = 1024KB

1 GB = 1024 MB

Note: when identifying the disk capacity, the hard disk Manufacturer uses the measurement method of 1KB = 1000 bytes instead of 1KB = 1024 bytes. Therefore, the actual capacity of a hard disk with a nominal value of 60 GB is about 8 GB, which is completely normal.

Bit is usually used to indicate the processor bit Width, memory bit Width, bus bit width, and memory bit width.

Taking the memory bit width as an example, let's talk about the importance of bit width. We know that the bandwidth of a video card is not only related to the clock frequency of the video memory, but also closely related to the data bus bit of the storage unit. Therefore, when you purchase a video card, you must not only pay attention to the video memory type and operating frequency, but also the data bus bit of the video ).

The memory bandwidth is calculated as follows:

Memory bandwidth = memory operating frequency (MHz) x memory size (bit ).

Example:

Video Card 1: GeForce2 MX 200-Bit Width: 64bit, working frequency: 166 MHz.

166MHz × 64bit = 10624 Mbit

Converted to bandwidth: 255.24mbit bandwidth 8 = 1328 MB/s

Video Card 2: GeForce2 MX 400-Bit Width: 166 bits, and the operating frequency is also MHz.

166 MHz (operating frequency) x 21248 bits (memory size) = Mbit.

Converted to bandwidth: 21248Mbit bandwidth 8 = 2656 MB/s

It can be seen that the number of digits of the video memory is very important for the bandwidth of the video memory. The video memory bandwidth directly restricts the data transmission speed between the display chip and the video memory, which has a great impact on the performance of the video card.

Bps and bit/s

The unit time (second) is used to measure the number of data bits that flow from a device. The more bits flow per second, the higher the data transmission rate of the device.

(1) bps (modulation rate ):

Bps indicates the number of bytes transmitted per second. It is mainly used for network modulation equipment (Modem) or (ADSL) frequency modulation equipment.

Example:

The common Modem is 56 kbps, And the ADSL is 2 Mbps. Bps and bit/s belong to the same unit of measurement, but bps is only used for network modulation devices. Taking the 56 kbps Modem as an example, we can calculate its Byte/s (the number of bytes per second) as 56 kbps/8 = 7kB/s.

(2) bit/s (number of transmission digits)

Indicates the number of characters transmitted by a device per second. If the internal transmission rate of a hard disk is 240 Mbit/s, the number of characters transmitted by the device per second is 240 Mbit, if it is converted to Byte (Byte)/s (second), it is equivalent to 240Mbit Bytes 8 = 30 MByte/s (Abbreviation: 30 MB/s ).

Dpi (points/per inch)

Dpi is an important parameter for measuring the resolution of a printer. When purchasing a printer, we usually notice that the larger the value, the more expensive the printer is. Why? First, we need to understand the concept of dpi. dpi refers to the number of printable points per inch. For example, 500 dpi indicates that 500 points can be printed per inch. The higher the value, the finer the output result, and the higher the price.

For the mouse, dpi is used to measure the number of points that can be detected each time the mouse moves 1 inch. Generally, the higher the number of points, the higher the resolution of the mouse, and the more accurate the mouse positioning ".