ตัวแดงนั่นล่ะครับที่ทำให้ตัวท่านหลงประเด็นของตัวเอง อาจจะเกิดจากความเคยชินของ Gaming PC ก็เป็นได้
แต่ท่านต้องไม่ลืมว่าโลกเราไม่ได้มีแต่ Gaming PC ซึ่งมีจำนวนน้อยเมื่อเทียบกับตลาดอื่นเช่น Office PC หรือServer
Info: The +12V rail is the main power rail in modern computers.
Modern computers draw 70%-95% of their power from the +12V rail,
and the power available at +12V should make up at least 80% of the total wattage, preferably 90% in enthusiast units.
It powers:
CPU
Graphics card
Main motherboard chipsets
Hard drive motors
Optical drive motor
Most fans
Water cooling pumps
PCIe cards
Most PCI cards
................
Info: The +5V rail used to be the primary power source, but has since fallen out of major use.
Even though it isn't a major power source, many of the things it powers are vital, so it must be kept tightly regulated.
It also powers external USB devices like keyboards and flash drives and such.
It powers:
Some motherboard chipsets
Hard drive circuitry
Optical drive circuitry
Some fans
Some PCI cards
USB devices
.....................
Info: The 3.3V was also a major power source in old power supplies, though not today.
It plays many minor roles, and should still be just as tightly regulated as the +12V and +5V.
It powers:
Some motherboard chipsets
RAM modules
Graphics card onboard control circuitry
Some PCI cards
...........
+5VSB
Nominal value: 5.00V
Allowed voltage variation: +/-10%, 4.50V - 5.50V
Preferred voltage variation: +/-3%, 4.75V - 5.25V
Allowed ripple: <120mV
Preferred ripple: <50mV
Info: The +5VSB is an often overlooked, but still quite important rail. It doesn't provide much power;
rarely more than ~1.5A (7.5W) at the absolute most. However, this is the rail that keeps runs the circuitry that starts your motherboard,
and powers the memory that stores the date and time and BIOS settings. Its power rating should not be added to the PSU's total output rating.
It powers:
Motherboard start-up circuitry
BIOS ROM
CMOS RAM
Charges CMOS battery
..............
-12V
Nominal value: -12.00V
Allowed voltage variation: +/-10%, 10.80V - 13.20V
Preferred voltage variation: +/-5%, 11.40V - 12.60V
Allowed ripple: <120mV
Preferred ripple: <80mV
Info: This rail is not used. Your PCI slots have a pin that is intended to deliver -12V power.
However, no PCI device has used -12V in over ten years. It is kept on as legacy support,
and to keep from "technically" violating PCI specifications. Its power rating should not be added to the PSU's total output rating.
It powers:
Nothing
..........
-5V
Nominal value: -5.00V
Allowed voltage variation: N/A
Preferred voltage variation: N/A
Allowed ripple: N/A
Preferred ripple: N/A
Info: The -5V rail was removed from the ATX specification with revision 2.0, and is not allowed on modern ATX power supplies.
If you have a PSU with a -5V rail, it is (or is based on) an antiquated ATX 1.3 era power supply which were designed to deliver most of their power
on the +5V and +3.3V rails, and thus are not suited for modern PCs. It may have had the +12V rail beefed up,
but that can't compensate for the outdated design. Any power supply with a -5V rail should not be used with modern PCs.
In the cases where a PSU does have it, its power rating should not be added to the PSU's total output rating.
Comment