Every single time, since the beta's release, I can play for about 5-10 minutes and then everything begins to slow down until the entire game freezes. Open the task manager and the memory used is >50% of my CPU and ~1.5k MILLION memory being used (In contrast, the most graphically demanding game I've ever played usually took around 10% of my CPU and no more than 500k memory and this game is FAR from the most graphically demanding.)
Please upload your DxDiag.txt as explained in my signature then I'll check what hardware you have and probably give you some advice how fix your problem. PA need lot of memory to work. 1.5GB it's not a lot actually. PA can easily use 4-5GB RAM when you play on many planets.