* Larger/more/better heatsinks
* Better voltage regulation, ripple, and such
* cleaner PCBs redesigned with the benefit of time vs the first gen X-series
maybe other pluses but afaik it's all improvements on the X-x60 vs the old X-x50 units.
For pictures of the internals see page 4 of the JonnyGuru reviews.http://www.jonnyguru.com/modules.php?na ... 4&reid=169http://www.jonnyguru.com/modules.php?na ... 4&reid=202
oh and "ferky" on the forums at JG listed these differences between the 560 and 650. Go to the seasonic website and compare the 560 to the 660 to see how they compare if the 560 to 650 comparison confuses you.
* X-560 has few cm longer cables than X-650, 2x PCI-E 6+2 (X-650 has 4), 1x 3,5" floppy (X-650 has 2), 1x 8pin EPS12V (X-650 has 2 + 1x 4pin). 5x 5,25" Drive connector (X-650 has 8 )
* X-560 has a bit stronger fan (difference is 200-300RPM @12V), but probably not louder (because the PWM kicks in)
* Transient stage is a bit rearranged (positions of MOV, thermistor and fuse are "hidden" behind the relay)
* Heatsinks on the primary stage are colored in orange/gold on X-560
* PFC Mosfets on the X-560 are assembled in a TO-220 case which has an substantial advantage over TO-220FP (FullPak) in X-650 (in aspect of power dissipation).
* Mosfet trasistors on the switching section of the X-560 have a bit lower typical RDS(on) then the ones inside X-650 (which has a bit powerfull ones).
* PWM controller (CM6901) on the X-560 is no longer placed on the main PCB but on a small daugtherboard (opposite of the X-650).
* The +3.3/5V secondary Mosfet transistors in X-560 have a lower RDS(on) and have higher current limits on high temperatures (and also higher peak/pulse values).
* Some of the electrolytic capacitors on the secondary have higher values in X-560 (than the ones in X-650).
* Secondary +12V Mosfets in X-560 have better heatsinks (lower °C/W) than the ones in X-650.
* The PS223 monitoring integrated circuit in the X-560 has a bit of a help from a couple of LM393 Voltage Comparators (which isn't the case on X-650).
* Some smaller transformers are different between those two PSU (nothing too important).
folowed by the comment "all those improvements are really not important (except maybe for number of cables/connectors in X-650, if they are needed)."
Short answer is buy whichever is cheaper unless you want to buy the latest and greatest in which case get a x60 wattage.