What should I do if the startup speed is very slow after installing the system?

The speed of booting is not only related to the system, but also related to your hardware settings. Please check one by one:
a. In the self-test form, look at the mode of the hard disk, DMA mode is normal. The PIO mode is extremely slow. If it is PIO mode, please enter the BIOS and load the default value, and then turn it on, it should be changed back to DMA.
b, in the power-on self-test form, see if the CD-ROM is connected to the slave disk. If it is, it will seriously slow down the boot speed. Because the system detects the master disk first at startup, and then detects the slave disk, if the master disk is empty, it takes a few seconds here. Please turn off the computer and take the optical drive back to the main disk. It is also possible to move the hardware, that is, set the main disk to “ld”; in the IDE attribute of the CD-ROM drive. Some optical drives are set at the slave when they are shipped from the factory. If you have never noticed it, please pay attention to it now!
c. The hard disk (parallel port) should use 80-core data cable. Do not use 40-core cable. The optical drive line is replaced. The speed of the optical drive line can only reach DMA33, and the speed of the hard disk can reach DMA100 or DMA133.
d, a new generation of motherboards added SATA hard drive interface. The user's hard drive is generally only one piece. That is to say, there will always be an IDE port or a SATA port that is idle. Each time the system is turned on, the system must detect each hard disk interface. An interface that does not have a device attached will consume a few seconds of time due to detection. So this type of motherboard starts the scroll bar and rolls a few more turns (such as Intel 865 and later). We should turn off the idle IDE or SATA channel in the device manager. When starting, you can reach the ideal state of rolling one and a half. If your hard drive is a new high-speed, high-density hard drive, the progress bar will be less than a lap.