This is an HP Smart Array P420, a plug-in PCIe card that connects a server's hard drives and SSDs to the system and groups them into RAID arrays for redundancy and speed. The 2GB module fitted here is HP's flash-backed cache: paired with an HP capacitor pack the controller runs write-back caching, and without a pack it runs write-through instead.
Tested working. Controller and its 2GB FBWC cache module, with the full-height bracket fitted; heatsink seated. HP service-tag and serial labels present and legible on both boards. HP server pull, light handling marks.
One HP Smart Array P420 2GB FBWC 6Gb SAS RAID Controller 633538-001 No Capacitor.
Fitment
A Smart Array P420 for HP ProLiant Gen8 — with the 2GB cache module fitted.
Eight internal 6Gb/s SAS ports across two mini-SAS connectors, hardware RAID up to RAID 6 and 60 with no licence key, on a PCIe 3.0 x8 card.
HP 633538-001 · Smart Array P420 · 2GB FBWC module 633543-001 · 6Gb SAS · PCIe 3.0 x8
Server · ProLiant Gen8 · PCIe 3.0 x8
DL360e/p, DL380e/p, DL385p, DL560, ML350e/p, ML310e and similar Gen8
Fits
• HP ProLiant Gen8 servers with a spare PCIe 3.0 x8 slot. HP lists the P420 for Gen8 — the G6/G7 equivalents are the P410 and P411 instead.
• RAID 0, 1, 1+0, 5, 50, 6 and 60 — HP once sold RAID 6 and 60 here as a licensed add-on and later folded them into the base firmware, so on this card's V6.42 firmware they need no licence key
• Eight drives direct-attached, or more through an expander backplane. 6Gb/s SAS and SATA, HDD or SSD.
It also runs in non-HP servers and desktops, with one quirk: on some non-HP boards the option ROM can stall at POST, and disabling the option ROM for that slot is the usual fix.
Four things people get wrong
• The FBWC capacitor pack is a separate part, and this sale is the controller and cache module. HP powers the cache backup from a supercapacitor pack (HP 660091-001 / 660092-001 / 660093-001, which differ only in cable length). Without one fitted the controller reports that the cache is disabled and runs write-through instead of write-back — it works as a RAID controller, and the write-cache speed-up returns once a pack is fitted.
• A full-height bracket is fitted. The board itself is low-profile, and HP shipped both bracket heights — a 1U or half-height slot needs the low-profile bracket, which is a separate part.
• SAS cables come from the chassis. The two ports are internal mini-SAS (SFF-8087). In a ProLiant that is the server's backplane cable; outside one, a forward breakout SFF-8087 to 4x SATA or SFF-8482.
• This is a RAID controller. HP-branded passthrough (HBA mode) is available on recent firmware, but it is not LSI IT mode. It is also a 6Gb/s SAS-2 card — 12Gb drives run, but at 6Gb.
Cache size comes from the module: the board part number carries no capacity. This one has the 2GB module (HP 633543-001) fitted.
Fitment and part-number questions welcome — message us through eBay.