zarcondg
New Head-Fier
- Joined
- May 17, 2010
- Posts
- 12
- Likes
- 0
I repeat...
Quote:
3.3V = PCI, and PCI express... YES!, if the computer is new enough to have them. (Remember ISA, and 16bit ISA) lol
3.3V on other parts, Depending on age of the computer.
The 3.3V used to power the older computer core stuff (CPU, RAM, possible chipset). digging deep into past memory, 200MHz Pentium I think era. Before that there was NO 3.3V rail. The CPU's either ran on 5V or sat behind a regulator. Before 3.3v (ATX and newer), 12V was the dirty power reserved for disk motors, and maybe fan motors. The 5V was the "clean rail" to drove digital stuff, in the old IBM AT, and "Baby AT" computers.
After the 200MHz Pemtium-ish era, CPU's and other stuff got faster, smaller, and required lower voltages. The 12V rail got the burden of all the stuff that had previously ran on 3.3V (or 5V way back).
The AT to ATX transition happened somewhere between the 486, and the Pentium days. Then the P4 required even more power, and we got the four pin yello/black plug to go with the other motherboard plug (And ATX12V was borne). Then they added more plugs for SATA, Graphics, etc.
The 16bit-ISA replacement, PCI remains to this day. "O" and some AGP stuff used 3.3V.
Quote:
PCI and PCI Express cards can use all three rails.
3.3V = PCI, and PCI express... YES!, if the computer is new enough to have them. (Remember ISA, and 16bit ISA) lol
3.3V on other parts, Depending on age of the computer.
The 3.3V used to power the older computer core stuff (CPU, RAM, possible chipset). digging deep into past memory, 200MHz Pentium I think era. Before that there was NO 3.3V rail. The CPU's either ran on 5V or sat behind a regulator. Before 3.3v (ATX and newer), 12V was the dirty power reserved for disk motors, and maybe fan motors. The 5V was the "clean rail" to drove digital stuff, in the old IBM AT, and "Baby AT" computers.
After the 200MHz Pemtium-ish era, CPU's and other stuff got faster, smaller, and required lower voltages. The 12V rail got the burden of all the stuff that had previously ran on 3.3V (or 5V way back).
The AT to ATX transition happened somewhere between the 486, and the Pentium days. Then the P4 required even more power, and we got the four pin yello/black plug to go with the other motherboard plug (And ATX12V was borne). Then they added more plugs for SATA, Graphics, etc.
The 16bit-ISA replacement, PCI remains to this day. "O" and some AGP stuff used 3.3V.