SFX and TFX PSUs

[ullbeking]

Hello!

I'm just curious, apart from size and shape, what are the major functional differences between SFX and TFX PSUs? Are there specific advantages of one over another? Of course, using a full-sized ATX PSU is often not desirable when building and SFF machine, so that really leaves SFX and TFX.

Generally, my "go to" brand for ATX PSUs is Seasonic. For SFX and TFX PSUs, what brands and models do people prefer? Thanks!!

Kindest regards,

ubk

 

[Alexreffand]

Hello!

I'm just curious, apart from size and shape, what are the major functional differences between SFX and TFX PSUs? Are there specific advantages of one over another? Of course, using a full-sized ATX PSU is often not desirable when building and SFF machine, so that really leaves SFX and TFX.

Generally, my "go to" brand for ATX PSUs is Seasonic. For SFX and TFX PSUs, what brands and models do people prefer? Thanks!!

Kindest regards,

ubk

Don't forget flex-atx, which has had more discussion here than tfx.

 

[Smitty2k1]

SFX is definitely a lot more mature in the consumer and enthusiast market than TFX or Flex-ATX.

For SFX the premium choices are Corsair (SF450 and SF600) and Silversone (the newest generation 500W and 650W)

 

[ullbeking]

SFX is definitely a lot more mature in the consumer and enthusiast market than TFX or Flex-ATX.

For SFX the premium choices are Corsair (SF450 and SF600) and Silversone (the newest generation 500W and 650W)

Thanks for the info, Smitty2k1. (For SFX I've been looking at Seasonic, which is my go-to brand for PSUs.). Also, I've heard that SFX (and TFX, Flex-ATX) is generally louder than a very high quality ATX PSU. Is this true?

 

[Smitty2k1]

Thanks for the info, Smitty2k1. (For SFX I've been looking at Seasonic, which is my go-to brand for PSUs.). Also, I've heard that SFX (and TFX, Flex-ATX) is generally louder than a very high quality ATX PSU. Is this true?

Most users using the SF600 with a 7700k or 8700k and GTX 1080ti note that the fan rarely spins on their SF450/SF600 even under high load. I believe that the fan in the SF450//600 is set to turn on when the PSU reaches a certain temperature and if you have your computer in an air conditioned room and it is intaking outside air (instead of recycled air from within the case) it stays cool enough. Thus, I would say it is every bit as quiet as an ATX PSU.

For my Silverstone PSUs, I've found them to be a little nosier than ATX equivalents because they have 92mm fans instead of 120mm fans and the fan curve is set based on load not on temperature. That said, when my open air graphics card is under load it is definitely the loudest item in my case.

If you're running a mITX system with a big graphics card it is a no-brainer to use an SFX form factor PSU. If you're running a CPU only system I'd suggest looking at something like a Pico PSU.

TFX and Flex-ATX can certainly do interesting things, and I think a user over at SFF Network Forums developed a relatively high capacity version, but the fan is so tiny I'm positive noise would be more of a concern than with SFX.

 

[Neapolitan6th]

Most users using the SF600 with a 7700k or 8700k and GTX 1080ti note that the fan rarely spins on their SF450/SF600 even under high load. I believe that the fan in the SF450//600 is set to turn on when the PSU reaches a certain temperature and if you have your computer in an air conditioned room and it is intaking outside air (instead of recycled air from within the case) it stays cool enough. Thus, I would say it is every bit as quiet as an ATX PSU.

For my Silverstone PSUs, I've found them to be a little nosier than ATX equivalents because they have 92mm fans instead of 120mm fans and the fan curve is set based on load not on temperature. That said, when my open air graphics card is under load it is definitely the loudest item in my case.

If you're running a mITX system with a big graphics card it is a no-brainer to use an SFX form factor PSU. If you're running a CPU only system I'd suggest looking at something like a Pico PSU.

TFX and Flex-ATX can certainly do interesting things, and I think a user over at SFF Network Forums developed a relatively high capacity version, but the fan is so tiny I'm positive noise would be more of a concern than with SFX.

The SFX PSUs (non SFX-L) only max out at 92mm fans including the corsairs. Some older Silverstone models use 80mm fans, but I believe the newer models are adopting 92mm fans for their SFX PSUs.

If your case supports SFX-L PSUs, you have the option of using 120mm fans for less fan noise however only Silverstone, be Quiet, and very other brands make SFX-l psus.

TFX and Flex ATX psus can be quite interesting. I believe Flex-ATX is used more in the enterprise enviroment. The best unit I've seen is an FSP 700 watt 80 plus platinum rated unit.

Do pay careful attention to the cables included as some server oriented PSUs don't always have the cables you may need.

For TFX I know Silverstone has released a new 350 watt unit which looks promising. I believe either Seasonic or Delta markets a 400 watt TFX PSU which looks pretty good as well.

In general the chance of fan noise with TFX and Flex-ATX will be higher as the fans need to run at higher rpms to make up for their reduced size.

Examples:

SFX vs large ATX (92mm fan vs. 140mm)

SFX-L vs SFX (120mm vs 80mm fan here)

TFX: (sfx vs. TFX)

Flex ATX:

Do note FlexATX PSUs can vary greatly in length and fan placement.

Also, TFX and Flex-ATX PSUs are almost always non-modular. Some adventurous sorts will custom sleeve modular cables for these units and will replace the included fans for ones that run quieter.