Seasonic X-Series 750W: Potent for the Price
by Martin Kaffei on April 13, 2010 11:13 PM EST- Posted in
- Cases/Cooling/PSUs
- Seasonic
- PSUs
X750: Potent for the Price
With the X-series, Seasonic delivers an outstanding performance. It's not only the high efficiency but also the good voltage quality and EMI friendly topology that make the X750 one of the most interesting power supplies on the market. With its double-sided circuit board, Seasonic sets the bar quite high and the semi-passive cooling will be great for users that frequently run at sub-50% loads. While the Enermax Pro87+ and Modu87+ are quieter at high loads, they're noisier at lower loads and still audible at sub-20%; with the fan shut off below 20%, the X750 is truly silent at low loads. Furthermore, the Sanyo Denki fan is a high quality design and should last a long time; the classical ball bearing is out of style and Enermax chose its Twister models wisely.
The selected line filtering stage from Yunpen is an excellent choice for interference suppression during relatively low loads; many manufacturers try to save money here in order to cut down resistance, which prevents optimizing the efficiency. Even though they are not necessary for a good thermal solution, it's good to see the continuing usage of Japanese capacitors. The 105 °C variants last a very long time and there are plenty of capacitors on the secondary circuit to provide good voltage filtering. While the idea of integrating a DC-to-DC converter with the cable management PCB may not have been their own, in practice it works well and their implementation is very good. Overall, the processing and soldering quality are very clean and the build quality is top notch.
In terms of connectors, the X750 is well equipped. Users get four 6/8-pin PCIe connectors and eight SATA/Molex connections, allowing for a wide spectrum of HDD/DVD/fan configurations. Only triple-SLI computers would need more connectors, and we wouldn't recommend running such a system off a 750W PSU—and we wouldn't generally recommend 3-way SLI at all. For modern GPUs like GF100/Fermi (GTX 470/480) and Cypress (HD 5850/5870), the X750 will work well, though SLI with Fermi will need a larger PSU. The cable sleeves are well done and help keep everything looking neat and organized, as does the fully modular cable system. What would help now would be some aftermarket cable packages for users that need/want longer or shorter cables, but even without those the modular cables will make this PSU simple to install in a case. The dimensions of the X750 are also small considering the rated output.
The DC-to-DC converter and high voltage output on the +12V rail makes the X750 a great fit for users running quad-core processors with SLI or CrossFire GPUs. However, if you have an older system you won't need to worry as 125W on +3.3V and +5V are still more than adequate. On 230VAC grids, the Seasonic X750 reaches up to 91% efficiency, but even on 115VAC the 89% efficiency result is nothing to sneeze at. [Gesundheit!] The relatively large voltage drop on the +5V rail is a minor point of criticism, but the 5V rail isn't particularly important for a modern system. The small amount of ripple is very welcome, and the resonant topology reduces ripple at high load.
Seasonic started out building PSUs for a lot of other companies, but these days they're focusing more and more on end users. With improved build quality and aesthetics, a 5-year warranty, and a very competitive price they have a lot on their side. The X-Series is everything you would expect from a modern 80 Plus Gold certified power supply. It will work great with anything from entry level PCs up though high-end SLI/CrossFire systems. The only thing missing from the X-Series are products targeting moderate users (i.e. sub-500W PSUs) as well as 1000W+ behemoths suitable for running GTX 480 SLI.
The Seasonic X750 is available starting at $170 (150€), so as usual quality doesn't come cheap, but the current price is $50 less than the competing Enermax Modu87+ 700W and still less than the non-modular Pro87+ 700W. With similar qualities and performance (we'd give Enermax a slight edge in overall performance), the price gap makes the X750 is an easy recommendation if you have to decide between the two. However, if you're planning on running at higher loads, Enermax can do so without generating as much noise.
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MadMan007 - Wednesday, April 14, 2010 - link
I hope they come out with some milder wattage units for those of use running 'normal' systems with a single GPU and maybe some non-ragged edge CPU and GPU overclocks. 83% efficiency at 10% of load is great.7Enigma - Wednesday, April 14, 2010 - link
This was going to be my comment as well. I build average systems with the highest performance/$ so currently have a C2D with 4870 and will be looking in the next year to make the jump to quad cpu /5XXX gpu. With the fantastic idle consumption of both cpu and gpu the amount of time at or below that 20% level for this PSU is considerable.Give me the 500w version that is 85% @ 100w for <$125 and I'm sold.
jonup - Wednesday, April 14, 2010 - link
Genuin question (not being surcastic):What is the big obsession with efficiency? 85% vs 87+%? Does it really matter?
I use a OCZ's modular power supply and at full load (OCCT PSU) voltages remain stable, it's quite and I do not justify paying extra $100 for 3-5% efficiency. It's not like I am using $30 PSU. What am I missing?
Alexstarfire - Wednesday, April 14, 2010 - link
Lower power bills. IF you maxed out a 750w then a 3% difference equates to at least 22.5w. Sounds like nothing, but if you leave your computer on 24/7 it adds up pretty fast. That's 540w per day so let's say 1Kw every 2 days. $.10, obviously this will vary the most since cost per Kw of electricity varies depending on location, every 2 days, that's roughly $18 per year.I doubt most would get anywhere near this, but expecting about $10 per year could be realistic depending on your computer specs and usage habits. So if you can get an extra 3-5% for less than $30-$40 then it's probably worth it. Though that's assuming the PSU lasts that long. If you can get more than 5% then it's probably almost always worth it. :P
Lots of variables that really just depend on the individual. Very useful for someone like me that does a ton of gaming and video conversions.
LordanSS - Wednesday, April 14, 2010 - link
Since we're on the topic of wattage and efficiency, I was wondering if I could get input from people about what "good", wattage would be for a PSU running a quad-core CPU (125W TDP, thereabouts), a 5970 (or wattage-equivalent video card combo) and 3 to 4 7200rpm mechanical HDDs?I was initially thinking about going with an 850w PSU, but if I can get "lower" with a big enough headroom for future component upgrades (like GPUs, that might consume more power), that'd be good.
Thanks in advance.
sviola - Wednesday, December 29, 2010 - link
Try using this tool:http://extreme.outervision.com/psucalculatorlite.j...
ekerazha - Wednesday, April 14, 2010 - link
On the contrary, the JonnyGURU review says the Seasonic X-Series performance are better than the Modu87+ series performance... who is wrong?C'DaleRider - Wednesday, April 14, 2010 - link
Given that AT always has spurious results in their load testing when compared to other reputable power supply testers, like at JonnyGuru, HardOCP, and Hardware Secrets, I'd tend to think AT still has yet to set up their Chroma properly.The aforementioned sites all showed a 1% voltage regulation on all rails yet AT has the 5V rail at 5%......inferior testing from AT. And when will AT learn those graphs are almost worthless? I'd really suggest going to JonnyGuru and look at charts with numbers, so you can see what the actual load being put on the power supply during testing and what stability the various rails demonstrated, along with actual captures from the oscilloscope of the ripple/noise generation and captures of the overshoot transient tracings.
AT, while great at motherboard, cpu, and video card testing, is waaaay behind in power supply testing and while better than some sites, is almost becoming worthless in their results, esp. when compared to more reliable testers on the web.
ElBurroMaron - Wednesday, April 14, 2010 - link
*lol* and what exactly makes you the expert? Just because you don't understand the graphs you conclude they're bad? And you think testing with a shoddy 3k Sunmoon is so much better than doing it with a 30k Chroma?I'd also love to see o-scope shots and a little more on loading scales but hey, maybe it'll still come one day. Maybe asking nicely and suggestion what could be added is better than posting such a stupid comment as yours?
MrSpadge - Wednesday, April 14, 2010 - link
I got my Modu 87+ 500W for 110€ and it's just perfect for me.. I love it! Kind of.