So my SFF build that can only hold 5 drives is full and I'm moving my drives to an Antec 1200 with x4 iStar DE350SS. When I started my SFF build, 3TB was the most cost effective setup. However, I'm thinking about transitioning to a 4TB setup. The x5 3TB drives that I currently have are 7200RPM Seagates. So if I switch out the parity for 4TB WD Red (which I believe are 5400RPM), would I see a huge performance hit on my 3TB drives? Granted, I plan to switch them out for Reds once they show signs of failure. In general, is it better to a have a faster parity drive or doesn't really matter for data storage purposes?

 

Edit: Also, I wanted to confirm if I would be fine PSU-wise. I have a spare 650B-BEFX (rebranded fully modular Seasonic X) which I picked on sale for $80. According to the PSU guide, this would be fine for 25 Greens or 16 7200RPM drives. So hypothetically if only the first 5 drives were 7200RPM, could I still use 15 Reds? In fact, would 5900RPM Seagates even be an option or would I be pushing it? If necessary I could pick up a different PSU, but would like to use this one if possible.

There are differing opinions on this.

I always choose the fastest parity drive I can afford. This way when multiple writes occur on multiple drives, there's plenty of speed to handle it.

When creating parity for the first time the extra speed on a parity write makes it slightly faster.

When checking parity, you'll only go as fast as your slowest drive.

 

Here's some quick benchmarks on a HP micro server gen 8 with various models of 4tb & 3tb drives.  YMMV

The 3TB's are amoung the fastest I've owned.

 

7200 RPM 4TB Hitachi

root@unRAID:/var/log# dd of=/dev/null bs=4096 count=1024000 if=/dev/disk/by-id/scsi-1ATA_HGST_HDN724040ALE640_PK2334PCGTEKJB

4194304000 bytes (4.2 GB) copied, 24.5728 s, 171 MB/s

7200 RPM 3TB Seagate

root@unRAID:/var/log# dd of=/dev/null bs=4096 count=1024000 if=/dev/disk/by-id/scsi-1ATA_ST3000DM001-1CH166_Z1F2WE0X

4194304000 bytes (4.2 GB) copied, 21.8611 s, 192 MB/s

 

5900 RPM 4TB Seagate

root@unRAID:/var/log# dd of=/dev/null bs=4096 count=1024000 if=/dev/disk/by-id/scsi-1ATA_ST4000DM000-1F2168_W3005LMP

4194304000 bytes (4.2 GB) copied, 28.5082 s, 147 MB/s

 

5900 RPM 4TB Seagate hybrid

root@unRAID:/var/log# dd of=/dev/null bs=4096 count=1024000 if=/dev/disk/by-id/scsi-1ATA_ST4000DX001-1CE168_Z3014JCE

4194304000 bytes (4.2 GB) copied, 28.9672 s, 145 MB/s

 

I have this one for my parity.

I'm pretty happy with it.

 

HGST Deskstar NAS H3IKNAS40003272SN (0S03664) 4TB 64MB Cache SATA 6.0Gb/s 3.5" High-Performance Hard Drive for Desktop NAS Systems Bare Drive

http://www.newegg.com/Product/Product.aspx?Item=N82E16822145912