Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Coolmax leaves a lot to be desired

I've had experience with Coolmax over the years. I build computers for a living and as a hobby. These power supplies are sub-standard and generally last until the warranty runs out. The efficiency ratio is poor.The last PS I had from Coolmax not only failed 2 weeks after the warranty had expired but it also fried my motherboard and all the memory. Fortunately, AMD CPUs seem impervious to power spikes and my Opteron 185 sailed though. I wound up getting a Corsair PSU - which I highly recommend.