For high performance pool (means SSD ones), i always tried to avoid PCH and prefered PCIe linked directly to CPU. I'm maybe a bit paranoiac.

Western Digital had a simple goal in mind when launching the WD Red; they wanted the drives to be synonymous with SOHO NAS use, developing into the defacto standard for small NAS use. Their custom firmware dubbed NASware and related technologies get the WD Red ready for this specialized 24/7 operational task. The Red has all the features needed like no unnecessary head parking, drive tolerances that support RAID environments and3D Active Balance technology which reduces vibrational wear on the drives. WD has also pre-qualified the Red with leading NAS vendors and the host controllers found in most NAS systems. On the support side the drives come with a three year warranty and a dedicated support line just for WD Red owners. SPECIFICATIONS Model numberWD30EFRX InterfaceSATA Gb/s Formatted Capacity3TB/3000GB Form Factor3.5-inch Advanced Format (AF)Yes Native Command Queuein... Condition In addition, On some motherboards, you can have SATA ports that are bridged differently from others and in the way perform differently and it can have finally an impact on the overall pool performance. The obvious question may be then, what’s wrong with the WD Greens and other low power drives that have been performing NAS duty to this point? The answer is really about projected use. The WD Green for instance, while the leading low power drive on the market, wasn’t designed for the 24×7 access requirements that NAS systems require. The WD Red was engineered specifically for this duty, complete with customized NASware firmware which includes critical features like intelligent error recovery controls that prevent drives from dropping off the RAID due to long recovery cycles. The drives also are engineered with "3D Active Balance technology" which tunes the drive to eliminate vibration leading to improved reliability and overall performance. Experienced in NAS - WD Red is a reflection of the most extensive NAS partner compatibilitytesting list that is available on the market.* That means when you buy a NAS enclosure, you can trust that WD Red will be the most compatible drive available. Our pride is in our product and our vision is shared with our customers.

How about these alternatives?

WD Red hard drives and SSDs have been compatibility-tested by major NAS system providers with their NAS systems and components. Join the Inner Circle? The Inner Circle is a community of like-minded individuals who are passionate about the same things you are. You’ll have the opportunity to ask questions and get replies from me and other Inner Circle members who are dedicated to helping each other out. PS: Even with a 12 SSD pools it's hard to handle more than 2GB/s READ/WRITE throughtput within a ZFS Pool, so it can be enough for your pool. The first indicator to detect whether it is a SMR drive is the cache size. But do look for letters EFAX in the serial number this would mean SMR. Old drives (WDx0EFRX) had 64MB cache whereas new replaced drives (WDx0EFAX) feature 256MB. You can also read the serial number on the disk itself and compare it to a table bellow.

EE Store is a trading style of British Telecommunications Public Limited Company, which is authorised and regulated by the Financial Conduct Authority. It’s an interesting decision – WD is expanding their low-power 3.5" hard drive offerings with a second line at the same time Seagate exits the "green" market, claiming low-power drives aren’t really all that beneficial or quite frankly, special. The Western Digital Red family of hard drives is designed for the 1 to 6 bay SOHO NAS space, which is about as specialized as it gets. WD has several features that they’re touting as critical for the NAS user including; NASware specialized firmware, Intellipower low power spindle, robust NAS compatibility list, three year warranty and a dedicated WD Red 24×7 customer support line (1-855-55-WDRED if you need them). Reliability: Desktop drives aren’t typically designed for the demands of an always-on NAS environment. WD Red hard drives are designed to perform under tough conditions encountered in high-intensity 24x7 multi-user NAS environments. For a long time there was an obsession with ashift=9 vs ashift=12 because of various reasons. This has an impact on a variety of things including space consumption and performance. Using ashift=9 on 4Kn is particularly bad for performance. Several different things have been done over the years to try to make this work correctly. I don't recall what the exact current strategy is, but I believe it tries to optimize correctly.The next profile looks at a file server, with 80% read and 20% write workload spread out over multiple transfer sizes ranging from 512-byte to 64KB. Enhanced reliability - Since your NAS system is always on, a highly reliable drive is essential. With a 35% MTBF improvement over standard drives, the WD Red drive with NASware 3.0 is designed for the 24x7 environment. With the new Red hard drives designed for 24/7 home and SMB NAS usage, Western Digital still found ways to improve the power consumption of their new low-power hard drive over previous generation low-power hard drives. Across the board, the new Western Digital Red offered the lowest activity and idle power values. Startup power was slightly higher than the older Caviar Green models, but not by much.