Performance drop with fputs after writing more than 2,5GB. Why?
The main reason for all this is a Windows disk cache. Then your program eats all RAM for it, then swapping begins, and thus, slowdowns. To fight these you need to:
1) Open file in commit mode using c flag:
FILE* fp1 = fopen("D:\\largeTestFile.txt", "wc");2) Periodically write buffer to disk using flush function:
if(i%1000000 == 0){ // write content to disk fflush(fp1); clock_t ms = clock()-last; printf("Writting of %i Lines took %i ms\n", i, ms); last = clock();}This way you will use reasonable amount of disk cache. Speed will be basically limited by the speed of your hard drive.