1TB Seagate is running hotter than 320GB Western Digital

TechyV People,
I installed a software that monitors my computers internal temperature that includes HDD temp, CPU and motherboard.
The software is called speedFan 4.43. As you can see below, HD1: is running @ 51C compared to my western digital's 49C.
HD0: Western Digital Caviar Blue 320GB
HD1: Seagate 1B barracuda (ST31000528AS)
is this normal for a large capacity hard drive?

