[TEST, PIC HEAVY] Cheap eBay 5A TTL driver

Hey !
I recently bought one of those cheap laser drivers: 5A 12VDC Power Supply Driver for 445nm 450nm 3.5w NDB7A75 Blue Laser LD with TTL
Not to use it as an actual driver but to perform tests on it.
But hey, if it works fine I might use it with my NDB7A75.

So I started by making a test load with 1N4007 diodes and a 5W 1ohm resistor:


(the Arduino is just used to "switch on or off" the driver using the TTL port on it)
When the driver is powered, it takes about 5s for its "ready LED" to light up, after that it starts giving juice.
First thing first, the output voltage:


I measured that after about 30s of run-time, since the voltage seems to drop a bit over time (sometimes I measured 5.2V without any voltage drop but most of the time the voltage starts at 4.8V and drops to around 4.7V :confused: ).
Then I measured the current with my oscilloscope (by measuring the voltage across the resistor; 100mV = 100mA) to see if there was nasty ripples.
Start:


(don't forget to look at the bottom left and bottom right for the scales)

A bit closer:


During operation:


The driver is outputting about 1.2A at average here.
Which means that it outputs about 5.64W while the power supply was giving 6.24W (so the driver have an average efficiency of 90%).

A closer look on the ripples:


So yeah I'm not a pro about laser drivers but those ripples of about 300mA peak to peak seems a lot to me.
What do you guys think ?