Combining a few PSU and MOSO together
Combining a few PSU and MOSO together
Hi, I had 3 PSU and Mobo... from gen 1 to 6.... I was planning to use them again. My question is, there are some details about PSU around 12-5-3.3 V that confused me. I searched online and people gave different answers in forums. For example, some said the CPU uses 3.3V and others mentioned it uses 12V.
I found this information:
12: CPU (maybe) and GPU
5v: USB, HDD, maybe SSD and DVD drive
3.3: RAM and CPU (maybe)
Am I correct?
So basically, if I want to have just a CPU (90W), plus a voltage regulator (VGAs), 75W for the GPU, plus 2x RAM and an HDD with nothing else connected, then do I need 14A from the 12V supply? I assume RAM and HDD use less than 10W and it's at another voltage.
So basically, a 15-17A from 12V could work? I’m not talking about efficiency, just whether it would work or not. Am I right or am I missing something?
I believe it would be simpler to discuss in hardware terms. Which parts are you considering? What motherboard, CPU, RAM, and power supply do you currently have, and which components are you thinking of upgrading? If you need help estimating the power requirements for your new setup, you can use this website: https://outervision.com/power-supply-calculator
Hmm. Little calculation then, as RAM isn't on the 12V rail. CPU is on the 12V rail btw, you got that right.
90W + 75W + 12W (HDD use 12V 1A) = 177W / 12V = 14.75A. Of course you don't want to deliver exactly what is asked/required, so I'd definitely get a couple more Amps on the 12V rail just in case.
At one point, processors relied on 3.3 and 5v for most of their energy. Nowadays, 12v powers both the CPU and GPU. Both options were valid but not fully accurate. Very early power supplies provided most of their output at 3.3 and 5v. Currently, 12v is the standard. In practice, it’s usually unnecessary to understand these details. The power needed today mainly comes from graphics cards. Here’s a useful reference: http://www.realhardtechx.com/index_archivos/Page362.htm. Because a power supply only uses what it needs, exceeding capacity isn’t harmful.
so i believe after lga 1155 they thought about using a 12V cpu... nowadays, which devices will run on 3.3 or 5v? and i’m trying to figure out how much current i need. i’m currently using a corsair cx650m and it’s working well, but i want to understand more. by the way, one of these old power supplies is a queen qu330qu... with two 12v units, each rated for 12 amps, totaling 200w. is that acceptable for my system? the label says (5v 20a) and (3.3 20a), but it’s supposed to be 100w. and another one is a mazerati model with 3.3-28a, 5v35a, 12v25a. i know these old brands are outdated, at least the first one looks real, but i’m deciding between them.
The power supply with most of the amperage on 3.3 and 5v is outdated and not ideal for a newer processor. If you have to, expect integrated graphics. Or, at best a discrete card such as the gt1030 that consumes only 30w. A faulty power supply can damage any connected device.
So in reality, 3.3V and 5V aren't really needed in today's builds—they seem unnecessary since most setups use 12V. I'm not referring to an old configuration, but I want to understand how much current we actually need from those voltages on a modern PC. Also, does using two separate 12V power supplies cause any issues? I haven't used a dual supply PSU before, but I'm curious if it's just about the design inside or cable management differences.
3.3 and 5v remain necessary; they only require moderate amperage.
Most power supplies draw power from a single source.
They are organized into rails for safety purposes.
A psu typically has just one 24-pin connector for the motherboard.
No alternatives exist.
If a GPU needs two 8-pin connectors, it’s better to use two separate leads from the psu.
Avoid using one cable with multiple 8 or 6+8 pin connections to keep cable management simple.
Excessive demand for full 8-pin connections could strain a single cable.