Seasonic M12II 500W Power Supply Review

Testing Methodology

Processor: AMD Athlon X2 3800+ @2.6Ghz (s939)
Memory: 2GB Corsair XMS PC5000 DDR @ 500Mhz
Motherboard: DFI Lanparty SLI DR Expert
Graphics Cards: 8800GTS 320MB (Single & SLI)
Disk Drive: Pioneer DVD Writer
Hard Drive: Seagate Barracuda 250GB SATAII
Fans: 4X Nocuta 120mm 1200RPM Fans
Monitor: Dell Ultrasharp 1907FP (1280X1024)

For our complete power supply testing methodology, please go here: Hardware Canucks Power Supply Testing Methodology

The first thing that we should mention is that this is the final time we will be using this particular test system to test power supplies. It is growing a bit long in the tooth and we have been putting off replacing it for some time now but the next 400W-700W power supply review you see here will be using a new system (specs are TDB) so say adieu to this workhorse.


Efficiency Testing

Single GPU Tests




Single Overclocked GPU Test




SLI Test



The first question that probably popped into your mind when reading the beginning of this review is if the Seasonic M12II 500W could compete with higher-end units on the market. Well, as we can see this power supply really delivers in the efficiency department. It is one of the more efficient units we have seen in recent memory so it looks like the claim of 80% and higher efficiency holds true with this unit. However, since we really don’t have a way to test Seasonic’s claim of 85% efficiency, we will keep that claim up in the air.


Voltage Regulation Testing

+3.3V / +5V Voltage Regulation Testing

Unfortunately, our present test system does not put enough load on the +3.3V and +5V rails for them to move much during the tests. Thus, while we did monitor these two rails during all of the tests we chose not to include the results since the charts would look exceedingly flat. Be rest assured though that the M12II stayed well within ATX specified norms during all of the tests.


+12V Voltage Regulation Testing



Overall, the +12V regulation of this Seasonic power supply is extremely good even when it is pushed beyond what any sane consumer would load a 500W unit with. It should be noted that just because the M12II 500W passed even the most stressful test without much effort, putting the load of a dual G80-based system on a 500W power supply is not recommended.

You can also see that we did not conduct the SLI Overclock test since we do not conduct this test on 500W power supplies. That being said, the M12II impressed us with its poise across all of the tests and proved to us that Seasonic has produced what looks to be one heck of a power supply…but there are a few more tests left to be done.