True hardware RAID controllers contain dedicated processors (often with XOR acceleration) and cache memory that handle all RAID operations independently from the host CPU. In contrast, fake RAID (also called BIOS RAID or host-based RAID) relies entirely on your system's CPU and motherboard chipset.

Look for these specification markers:

• Dedicated RAID processor mentioned (e.g., "XScale IOP348 RAID processor")
• Onboard cache (minimum 128MB, often battery-backed)
• Support for RAID levels beyond 0/1 (e.g., 5, 6, 10, 50, 60)
• Independent management interface (usually via dedicated NIC/IPMI)

# Check Linux kernel messages for RAID type
dmesg | grep -i raid
# Should show either:
# "Hardware RAID detected: [controller model]" OR
# "Software RAID (dmraid/fakeraid) detected"

Most consumer-grade "RAID support" falls into the fake RAID category:

• Intel RST (Rapid Storage Technology)
• AMD RAIDXpert2
• NVMe RAID in consumer chipsets

These typically require add-in cards or enterprise motherboards:

• LSI MegaRAID (e.g., 9361-8i)
• Broadcom (formerly Avago) RAID controllers
• Adaptec SmartRAID

True hardware RAID appears as a single block device to the OS:

# True RAID device path example
/dev/sda  # Entire array appears as one disk

# Fake RAID requires special drivers
/dev/mapper/isw_xyz123  # Typical dmraid device path

Sample benchmark difference (4-disk RAID 5):

# Hardware RAID (LSI 9361-8i)
avg. write throughput: 1.2GB/s

# Fake RAID (Intel RST)
avg. write throughput: 450MB/s

When examining RAID implementations, the critical distinction lies in where the RAID processing occurs. True hardware RAID controllers contain dedicated processors (often with XOR acceleration) and onboard cache memory to handle RAID operations independently of the host CPU. In contrast, "fake RAID" (often called host-based or BIOS RAID) relies entirely on the system CPU for RAID calculations.

Look for these red flags in product specs:

• Mentions of "RAID BIOS" or "BIOS support for RAID" rather than dedicated RAID processor
• Reference to "Windows/Linux driver required" for RAID functionality
• Absence of terms like "RAID processor", "XOR engine", or "BBU (battery backup unit)"
• Common in motherboard specifications (e.g., Intel RST, AMD RAID)

Genuine hardware RAID controllers will typically:

// Example of checking RAID controller in Linux
$ lspci -v | grep -i raid
01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2208 (rev 05)
    Subsystem: Dell PERC H710P Mini
    Flags: bus master, fast devsel, latency 0, IRQ 16
    Memory at df3c0000 (64-bit, non-prefetchable) [size=16K]

Notice the dedicated RAID processor (MegaRAID SAS 2208) and onboard memory - hallmarks of true hardware RAID.

Linux users can identify RAID type with these commands:

# Check for mdadm (software RAID) arrays
$ cat /proc/mdstat

# Examine storage controller details
$ sudo hdparm -I /dev/sdX | grep -i raid

# Check driver modules (fake RAID often uses ahci)
$ lsmod | grep -E 'ahci|raid|megaraid'

Most consumer-grade "RAID" solutions (including motherboard implementations) are actually fake RAID. True hardware RAID controllers are typically found in:

• Dedicated RAID cards (LSI/Broadcom, Adaptec, Areca)
• Enterprise storage systems
• High-end workstation motherboards with dedicated RAID chips

The difference becomes apparent under load:

# Sample benchmark results (IOPS)
RAID Type         | Sequential Write | Random 4K Read
------------------|------------------|---------------
Fake RAID (RST)   | 45,000           | 8,200
Hardware RAID     | 190,000          | 32,500

When writing storage-aware applications, account for these differences:

// Example: Detecting RAID type programmatically in Python
import subprocess

def detect_raid_type():
    try:
        output = subprocess.check_output(["lspci", "-v"]).decode()
        if "RAID bus controller" in output:
            return "Hardware RAID"
        elif "ahci" in output.lower():
            return "Fake RAID"
        return "Software RAID or No RAID"
    except:
        return "Detection failed"