The old style of power supply is now called non-Modular. Notice the mess of cable that are permanently attached to the power supply. Well if you don’t need them all, which is likely, then you have to wrap that mess up and tie it somewhere inside the case.
In contrast, here is a modern Modular power supply:
Notice that there are no cables hanging out of this PSU at all. You only use the cables you need to run your system. Modular power supplies are a little more expensive, and they are only provided for larger sizes. 550 Watts is about the smallest Modular PSU that’s available.
Semi Modular Supplies
You can probably get by with a Semi Modular supply. In the previous picture, notice that there is a wide connector at the top left. This is the Motherboard power connector. This will always be used in a system, so there is very little advantage in making this connection modular. One might even argue that making this modular adds some losses to the PSU since there is resistance in any set of connections. I get Semi-Modular power supplies when I build a system:
This semi modular PSU has hard wired connections, at the bottom of the photo, for the mother board connections.
Here’s another Semi-Modular supply. Notice the detachable cables above and the MB connection cable rolled up in the box below. I have used the RAIDMAX Hybrid 530 Watt Semi-Modular supply for several smaller systems that I have built and it works very well. It is affordable at about $50 has a lighted fan and all except the mother board connectors can be detached. There are many modular choices at higher power output and prices.
Now that we know what we are talking about, let’s look at another reason, besides neatness in your system, for purchasing a semi-modular [or modular] power supply.
I’m upgrading a five year old system to SSD. And as I was connecting the new SSD drive, a connector on the 3 connector daisy chained SATA power connector broke. It won’t work this way.
And this Semi Modular supply has this connector permanently connected.
Two SATA power chains as well as the motherboard chain are permanently attached in this PSU. Sigh…
At least I can ball up the broken chain in the bottom of the cabinet and add a new chain to the PSU.
So I was able to get things working again with a new power chain connected to a port of the semi-modular supply. It would be a lot nicer to not have a cheap connector break, although the plastic may have simply dried out over the last five years. And nicer if I could have removed the broken chain and replaced it with an extra chain, that was provided, rather than balling up the broken chain at the bottom of the cabinet.