It does not mean though, that it is a total failsafe-in a random occurrence of things, your PS4 CMOS can breakdown at just about any point. The CMOS battery is not that fragile, and its performance can go on for as long as ten years. How Long Does the PS4 CMOS Battery Last Without Power? This forces the firmware to start over from the beginning and do everything the long way without taking any shortcuts or making any assumptions. What Happens When You Remove the PS4 CMOS BatteryĬutting power to that SRAM chip by removing the CMOS battery forces the contents of the chip to zero out. Since the firmware is just a program like any thing else, it can freeze up before initializing the graphics adapter, fan controller, or anything else. If the firmware is even the slightest bit buggy, it may fail to revise the parameters when there’s a hardware change or a failure. This is a fairly time consuming process so it doesn’t make sense to do absolutely everything each time the PS4 is turned on unless it’s absolutely critical.Ĭertain parameters need only be checked or calculated once, at which point they are stored in that SRAM chip until there’s cause to revise it. The system firmware performs a number of diagnostic routines to make sure that everything is in working order, and to take a look at what’s attached to it. The first thing that occurs when the PS4 is turned on is called POST, or Power-On Self Test. However, it need not do absolutely everything every time it is turned on. On the topic of reconfiguring everything, the system firmware does a lot of work to setup the PS4 into a state in which it can load an operating system. It’s also what prevents you from having to reconfigure everything when your PS4 is turned back on.
This is what allows your PS4 to maintain accurate time down to the second even when it’s turned off. However, power to the system’s real time clock and that small SRAM chip is maintained through a small battery located on the motherboard. When your PS4 is powered off, power to the CPU, hard disk, DRAM, GPU, etc… is cut. When it loses power, the information stored in it is lost. As you will see below, it will also provide a convenient method of disaster recovery. The reason for storing these settings in an SRAM chip rather than alongside the firmware itself on an EEPROM is historical, EEPROMs can only be overwritten so many times before they become unreliable. All of the configuration information such as boot priority, CPU settings, fan speeds, and the storage controller mode of operation are stored on this chip. This SRAM chip is used to hold firmware settings. What people refer to as CMOS is actually a small SRAM chip on the PS4 motherboard which traditionally was constructed using CMOS logic. It allows you to shut your PS4 down for an extended period of time and still have the correct time and date in place when you use your PS4 again. The CMOS battery in PS4 consoles is a small, round battery that helps you store the day, time, and month on your PS4. The word CMOS is an acronym for “ complementary metal oxide semiconductor”.