15k sas 3gbps vs 10k sas 6gbps drives

[gettothechopper]

we currently use servers with a raid 5 array of 5 x SAS 15k 250GB 3.5" 3gbps drives

we are speccing new servers with a raid 5 array of 4 x SAS 10k 600GB 2.5" 6gbps drives

any one have a clue if this would be faster / slower / the same? (roughly)

thanks!

 

[gettothechopper]

do you mean that the smaller platter size would actually increase performance due to the head having less distance to move?