>If files are sitting on the local drive, the second approach works faster (difference about 1 sec.). If they are located on the NetWork drive, the first approach is faster ~3sec. File is 5MB.
>
>I also can not find the optimum size in fread().

When I said 'round numbers', I meant ROUND, like 2048, 4096, 8192, 16384, 32768, 65536 and such :). With numbers which just have zeros when written in decimal, I wouldn't know which would give you better alignment and less overhead (or does it matter at all - simple matter of network being more or less loaded at some point may ruin your benchmarking).

I figure you'd need a little more testing, probably with the buffer size about four times bigger each time, to find what suits your OS/network the best. I can't imagine any rule here, it all depends.