Raid 6 vs raid 50 ?

[Nemoren]

I have :
8 Seagate Cheetah 15k 73gb hdds
1 Adaptec 3805 RAID 8ch SAS controller.

What would be faster:

two 4 drive raid 5s in stripe = raid50
or
one 7 drive raid 6 with a hot spare?

faster for reads, and faster for writes?

Is there another option for very fast random read and write ios?

I found ramsan, but they appear to be 30k
also found :
2 x HyperDrive4 Internal RAID System (0-32GB)
£2250 (+ VAT) $4390 (US)

does anyone have any good advice?

I need extream performance for under 5k.

 

[Guest]

RAID 6 would be marginally faster, but would also give the added benefit of allowing multiple drive failures. RAID 50 would rebuild the array faster with less performance degradation and is still very fast. I Use RAID 50 on most of my storage, but RAID 6 can be attractive on SATA arrays.