50w Chinese Laser power issues?

So I decided the pull the trigger on an ebay chinese 50w co2 laser knowing that it would take some tinkering to get it working right. Overall, I've been very impressed with the machine. The laser alignment was nearly perfect from the factory (about 1mm out from each extremity). The laser cuts and everything is working relitively smoothly. But I think there might be a power issue. I contacted the seller and he's working with me. But I just wanted some second opinions.

So here's the problem. I ordered some 1.5mm acrylic that I've been using to test the laser and it barely cuts through at 65% power 20mm/s. I have to make 2 passes to get the pieces to drop out. Similar results with same thickness mdf. Based on my impression watching other videos, that seems pretty poor for a chinese 50w laser. Please correct me if I'm wrong!!

I've already done a ramp test and focused the laser. The lense is clean and mirrors and aligned pretty well. Just to be sure, I made a cut near each corner of the machine and a few places in between with no increase or decrease in power. At the machine i have min power set to 15% and max power set to 75%. Some observations I've made are:
1. I have a 50.8mm focal length lense (not the 38.1mm like some other lasers I've seen which have greater power density)
2. I hooked up an amp meter and the tube pulls a consistent 18 milliamps at 75% power
3. The ground lead is wrapped around the laser tube probably 10 times near the exhaust. I haven't seen this on any of the other lasers.
4. When I use the pulse button, it will punch a hole through a wooden clothespin in a few milliseconds. Although, holding the pulse button and moving the axis manually yields the same results as running a program.

I would REALLY appreciate some input on this. If you have any please share! Thank you SO MUCH!

we have the same machine

ground lead from the laser is wrapped around our tube, shouldn't be a problem

we cut 3mm acrylic at 7mm/s and 45% min and max power so I guess you are going too fast.

I dont use over 45% as I havent got a mA meter yet and there doesn't seem to be much difference going higher than that

Mine cuts cleanly through 3mm acrylic @ 16-17mA and 10mm/sec

You running 110 or 240 volts?

Mine cuts through 3mm acrylic at 45% power (approx. 16ma) at 14mm/sec (and 6mm acrylic 65% power/20ma at 6mm/sec) both in 1 pass.