I'm thinking of getting an external FireWire 800 Hard Drive, and was just wondering how much better the performance of the FW HD will be, compared to my 7200rpm HD built into my MBP?
It depends on how fast the hard drive you are connecting via FW800 is.
As far as FW800, don't worry it is 'fast enough' for any hard drive you attach to it.
Well, if the FW800 drive is 7200rpm too, and 16mb cache (like my built-in one), will the FW800 drive be faster than the Serial-ATA drive?
No, the FW800 will never be faster than the internal SATA one you have in your notebook. That isn't to say, however, that there would be a noticable difference between a FW800 drive and a SATA drive in real-world use (mainly because the maximum transfer rates for both are never met in the real world).
What do you plan on using the FW800 for? If you're looking for the fastest solution possible then I would consider an eSATA drive with an eSATA expresscard.
No, the FW800 will never be faster than the internal SATA one you have in your notebook. That isn't to say, however, that there would be a noticable difference between a FW800 drive and a SATA drive in real-world use (mainly because the maximum transfer rates for both are never met in the real world).
What do you plan on using the FW800 for? If you're looking for the fastest solution possible then I would consider an eSATA drive with an eSATA expresscard.
No, the FW800 will never be faster than the internal SATA one you have in your notebook. That isn't to say, however, that there would be a noticable difference between a FW800 drive and a SATA drive in real-world use (mainly because the maximum transfer rates for both are never met in the real world).
I should also note that my 7200rpm RAID array *very noticeably* outperforms the old 5400rpm internal disk in my white iMac 24" with respect to READS.
The OP is comparing MBP Internal 7200rpm HD vs FireWire 800 HD. The OP is NOT comparing RAID.
Not sure how a 3.5" drive can fit internally into MBP... The assumption is that it'll compare laptop drives, since anyone who knows RAID will not be asking this question.
So the answer COMPARING INTERNAL 7200 2.5" drive to a similar drive on Firewire 800 is that there will be no bottleneck.
External 3.5" drive with firewire 800 will be faster than 2.5" internal drive. If you really want speed, get eSATA and a RAID.