I'm thinking that my PSU is getting a bit old and I would like to replace it. I'm wondering if I should go with SFX or SFX-L instead of ATX. I'm seeing a lot more SFX options: Silverstone, Corsair, Be Quiet! and Fractal Design. Obvious differences: price, volume and fan size. Question: given the current trend of near-silent operation with mostly fanless operation, is there any reason to not go with a SFX or SFX-L PSU for the majority of builds? It gives more flexibility in case selection and more space for cable management. Is there a significant difference in reliability or noise?
I've had a number of SFX PSUs over the years and I'd definitely recommend the Corsair SF 450 / SF 600 as they are very reliable and have 92mm fans with zero fan at low temps. Do read up on teh Corsair cables, as the supplied ribbon ones on the ariginal gen SF are hard to bend and fit. THere are alternatives from custom suppliers which help at a cost. Some of the newer SIlverstone SFX units have 92mm fans, which is a help. The original ones are 80mm and not so quiet The big advantage of SFX-L is that it has a 120mm fan, but is only larger in one dimension than an SFX PSU. I wouldn't buy and ATX PSU unless I absolutely had to, especially with SFX-L as an option.
Aside from size the main difference is price. You definitely get to pay the ITX tax on SFX power supplies to the tune of £20-30 for matching features. But in a smaller case that would be worth it for not tearing hairs out trying to make cables fit.
In theory SFX PSU's will have higher heat density, so may run hotter and louder than the comparitive ATX PSU.
Compared to a few years ago, a surprising number of options. SilverStone SX650-G Gold 650w Seasonic Focus SGX Gold 650w Be Quiet SFX-L 600w EVGA SuperNOVA 650 GM 650w Fractal Design ION SFX-L 650w Corsair SF600 Platinum 600w
The ribbon cables are only on the Corsair Gold rated SFX PSU's, they ship braided with the Platinum models. I hear thet are much better than the ribbon cables.
I’ve got the Silverstone SX650-G (92mm fan) in my current rig, and used a Silverstone SX500-LG (120mm fam) in my previous one. Both are solid. I’ve also used a Silverstone SX45-G previously, that had the 80mm fan and was a little noisier, but not much (though there were a couple of revisions and I think it was the earlier one that was considered ‘loud’). I guess unless you need a SFX power supply for your case you don’t ‘need’ a SFX power supply. But there is no reason not to go with one if you’re happy to pay the price: you’re not constraining yourself in terms of quality, power delivery or efficiency, and they open some options for different cases as you say.
I’m a big fan of the increasing trend to the petite form factor. If you over spec and your under the fan start/stop threshold (for semi-passive PSU’s) then the smaller fan is immaterial anyway. A PSU adaptor plate will allow you to use it in a normal case. Personally I would go with SFX rather than SFX-L, as the L-spec isn’t supported by some cases. Only real downside is cable length. SFF PSU’s tend to come with smaller cables.
I use the EVGA SuperNOVA 650 GM 650w unit in my fractal nano s. Needed an atx extender, but apart from that all the other cables were a suitable length. The need for an extender is more about cable management though. Main thing is the size of the psu helps my gfx card breathe a lot better than a full atx would in the same case. So really it's about your use case more than anything else I think
I do like the Silverstone SFX models - the short length cable kit is very flexible - much more so than those on my Corsair SF 600. I am happy with the Corsair, but Silverstone would've been the preferred choice though, weirdly, I couldn't find Silverstone units in stock greater than 500W at the time I was buying.
@silk186, it looks like you've woken up the Bit Tech unofficial SFX PSU Fan Club How's the Evolv ITX doing? Seems like a lifetime ago that I carted it up to London to hand it to you and meet Geddy Lee - happy days indeed. Stay safe.
I’ve picked up the short cable kit before I picked up the 500-LG, and then found I didn’t need it as the cables were about the same length as those in the box. So it’s sat here doing nowt for the last few years, I should probably bung it up on the marketplace and free up some space. The flat cables Silverstone use are very easy to work with though.
Yeah, I was all set to order the PP05-E short cable kit for my Silverstone SFX PSU, then I measured the cables I already had and all but a couple were actually shorter than the short kit versions! I do like the SS cables, nice and easy to work with and manage - I like that they're flat and also flexible so you can concertina them together with a zip tie to reduce the length without it becoming too bulky. Sooo much nicer to use than those horrid Corsair cables, which are truly awful. I'd love some custom cables but I cannot justify the cost given that what I have now work perfectly well and I don't have a windowed case In a wider context, whether I'd go for ATX or SFX would really depend on what case I was using (and to a lesser extent, if I was looking at an ATX case, whether I might have any plans in the future to go smaller). The great thing about SFX PSUs these days is that you don't need to compromise too much on power, noise or reliability. One caveat would be that you might need extenders / custom cables for SFX PSUs in bigger cases.
I keep going back and forth on size, my first custom-built was a smaller case, then I went with a bigger case, Cooler Master Storm Enforcer, then I decided I want to go smaller and have a Phanteks Evolv ITX but cooling is pants. I picked up a 280mm AIO and have 2x 3.5" drives in it currently which limits options with good airflow and a reasonable price. I'm looking at a Meshify C or maybe a mini. I'm thinking I may go ATX with my next build for additional M.2 slots.
Something nobody has mentioned is that cable lengths *are* shorter on SFX PSUs. While I had my Corsair Gold SFX PSU in a Corsair 450 before downsizing, I had to have the PSU semi-suspended in the air, inside the case, for the cables to reach far enough!
It will be interesting to see if my cases are built for SFX PSU as they are becoming more common. Given all the fanless designs, I don't think thermals will be an issue with SFX-L Cable length could be an issue though as paying a premium for an SFX PSU AND needing to build longer cables would add considerably to the cost.