I have recently been working on SSE2 insructions and have found that if I can get my data 16byte alligned, I can call much much faster mov commands. Right now I use the following hack to get my 16byte alligned data: void *AllignData(void *data) { return (void *)(((int)data + 15) &~ 0x0F); } void main { const int sizeofdata = 512; double *lotsofdata; double *tempptr; tempptr = new double[sizeofdata + 2]; // " + 2" because in the worst case scenario, we will find the first 16bytes alligned data 15 bytes into our buffer. lotsofdata = AllignData(tempptr); // do lots of CPU intensive SSE2 stuff here delete [] tempptr; lotsofdata = 0; // do not delete lotsofdata, just set it to 0, the memory it points to is no longer valid } I was just wondering if there was a better way to accomplish this, as it is not a a very clean method for accomplishing what I want. A solution in gcc and/or visual C++ would be great. I have tried many things to fix this to no avail... Thanx! Dwiel