Another thing you have to consider is what OS are you booting, is the drive defragmented, how is it connected (IDE ribbon cable vs SATA 1/2), how relatively new is the Pentium 4's technology vs the Core 2 Duo... There's a lot of factors, but generally, the Core 2 Duo should always top it. With Linux, my P4 system boots very very fast, but I have no doubt in my mind that if there was a Core 2 Duo system with Linux next to mine, it'll top it.