Normally when you use BlueStacks with computer you will get normal speed or actually slow. These problem because default system BlueStacks add your ram computer to using on BlueStacks (60MB to 750MB) only, so it makes BlueStacks to work slow.
Solving to make BlueStacks work fast you need to add more ram to BlueStacks to make BlueStacks work fast and not error. Below is how to add ram on BlueStacks .
1.First type start +R and type : regedit to visite to correct regedit of you compute in BlueStacks.
2.And then to correct memory of BlueStacks (ram of BlueStacks ) to size you want on address HKEY_LOCAL_MACHINE/Software/BlueStacks/Guests/Android/Memory .
3.The last you just restart BlueStacks and check setting of BlueStacks of ram size to make sure that your BlueStacks get ram size that you were add actually.
This is a way to help in BlueStacks work better and get high speed.