Bad modular design Silverstone ST45SF-G

There's been some discussion about the noise of the fan in the ST45SF-G, but I want to highlight the other design fault in the new Silverstone ST45SF-G modular SFX PSU. If you'd rather not read the whole rambling story below, in a nutshell: the pin-outs on the PSU are not mirrored compared to the motherboard pin-outs but they should be. This means you cannot create a perfect sleeved 24-pin ATX with this PSU e.g. like the ones Lutro0 makes.

Modular cables in an ATX system used to mean: not having a load of unused Sata and Molex cables hanging around in the case, ostensibly improving airflow but moreover helping the insides of enthusiast PCs to not look so messy. With the increased interest in sleeved extensions more manufacturers followed demand for modularity and enthusiast PSUs started to include fully modular connections including the ATX20+4 cable. Now modders could shorten and sleeve their cables without voiding their warranty. In an SFF case arguably cut-to-spec custom cables should be even more important to airflow and clean looks than with an ATX case. If the PSU is 8 inches from the motherboard power, why use a 14 inch cable?

The Silverstone Strider series have always been ideal PSUs to sleeve since the cables are wired 1-to-1. So when the new SFX unit was first announced, I cancelled my plans for sleeving the bronze power supply which comes with the SG05. I presumed the ST45SF-G was a direct upgrade and intended for use in the few cases which are designed for SFX PSUs. Although the bronze unit comes with an ATX adapter plate, I always thought Silverstone were just paying lip service to customers with mATX cases who already have a choice of shorter, but modular ATX PSUs. So here is the first picture I noticed on the Silverstone website.



If you imagine this orientation for the SG05, it looks great. The 24-pin ATX is at the bottom, would go directly down to the motherboard. The 8-pin EPS is on the right which matches how many mITX boards have that connector, and the PCIe is on the left which is the side the graphics card is on. However, later I saw that this picture is upside down compared to the ideal PSU orientation. Well that's a shame I thought, the EPS and PCI bundles will cross each other and I'll have to route the Sata/molex bundle different that I'd planned. But I was trying to look on the bright side, I could either flip the PSU or accept that the whole ATX-24 will be twisted. Thinking too about cutting each wire a different length to make the sleeves go in a nice curve to make it less obvious it's twisted.



Excuse the fake motherboard. You can see on the picture above that the length of the included modular cable is just arbitrarly 30cm. Too long for many mITX cases where the PSU is above the motherboard, and probably too short for many standard mATX cases. No problem, they can't please everyone I guess. However, compared to the bronze ST45SF the cable is much less flexible and the modularity becomes more of a hassle than a help. More reason to make my own.



A custom 24-pin ATX harness with wires around 7 inches will make this look good I thought. According to the diagram on the Silverstone website it is indeed 1-to-1 pinout. Nice and straight, or... ?



Then I actually looked at the cable. See for example the green and blue wires? They start at the one side and somewhere inside that ugly bundle they swap to the other side. I checked all the wires. All the pin outs are mirrored, yet stay on the same row. So there's no solution like just to twist the whole bundle. Each row would have to be twisted and then brought back together.



To illustrate how bad this would look on sleeved cables, here's some cheap extensions with each row folded over. I don't want something like this in my rig. Then better to have the crappy standard cable, but what about all the MDPC sleeving I have ready in my drawer? Maybe someone has an idea, or a question? I hope perhaps a Silverstone rep can explain about this bad design.

Thanks for reading.
Edited by WiSK - 9/20/12 at 2:23am

Edit2: This is how the pinouts look, as if you are looking through the front grill of an SG05.



1. Fan orientation doesn't matter. I found it hard to describe in my story, but it's not that the PSU was upside down or something, the pinouts should be mirrored but they are not. You will have to fold both rows of wires like I show in the last picture of the blue sleeved extension.
2. With only 7 or 8 inches between PSU and motherboard, there's no way to hide it. The only way is to bundle everything up into a jumbo heatsink like the standard cable.

Edit: Someone at [H] pointed out that pin 1 on the PSU side actually does go to pin 1 on the motherboard side, so the PCB is not mirrored, but it should be. Pin 1 should go to pin 12. For ideal situation so that you can have the sleeved wires going 1-to-1 from PSU to motherboard without twists, it should have been like this:


Edited by WiSK - 9/24/12 at 6:45am

Lutro0 has made an excellent video guide about how to sleeve double wires.

I have thought a lot about how I am going to sleeve my ST45SF-G. After almost 3 weeks since I made this thread I do have a plan now. But I managed to measure and crimp only 3 wires. So maybe I'm not the best to offer advice on how easiest to do it. Maybe you can look at the first picture in my post #3 above to help with the pinouts, and remember that the double wire from pin13 MB side goes to pin13 and pin20 PSU side.

1. The orange (3.3V) wire which is double on MB-side pin 13 and goes to PSU-side pins 13 and 20. It does work with a single wire from 13 to 13, but apparently the PSU uses pin 20 to fine tune voltages at load. I am planning to follow Lutro0's method and make the Y split halfway along the wire, so that I don't have to crimp two into one at the connector.

2. The red (5V) wire which is double on pin 4. I don't know for sure, there must be a reason they made it like that, but I'm planning to run just a single wire.

Of course I'll test with PSU tester before plugging in any real hardware.

I crimped some wires, but realised it's a bit late to continue. 10 more to do tomorrow.