FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 191608

Some key factors on Gen1 and Gen2 FortiGate-6000F Series.
- There are no restrictions on forming a cluster between a Gen1 and Gen2 FortiGate-6000F.
- Both versions can be managed by FortiManager.
- Gen2 version support starts from 6.2.4 B4008 build and all subsequent builds above 6.2.4 B4008 build
- Note that for Gen2 versions 6.2.4 GA B1116 should not be used as its not supported. Please contact TAC support to request for 6.2.4 B4008 special build for Gen2 units if needed as this is not available on
- Gen2 FortiGate 6000F can be upgraded to 6.4.2 GA B1749,
- Gen2 FG6X0XF-DC platforms need 6.2.6 B1158 / 6.2.7 B1179 GA and above. 6.4.2 B1749 does not include support for DC platforms at present.

Differences between Gen1 and Gen2 models.

1) Increase in RAM per FPC.

- 32GB (Gen1).
- 64GB (Gen2).

2) Change in Power Supply.

- Gen1 back panel includes three hot swappable 1500W AC power supply units (PSUs).
At least two PSUs (PSU1 and PSU2) must be connected to power.
PSU3 is a backup power supply and provides 2+1 redundancy. 

- Gen2 back panel includes three hot swappable 2000W AC power supply units (PSUs).
If connected to high-line AC power (200VAC or higher) each AC PSU supplies 2000W AC.
If connected to low-line AC (120VAC or below) each AC PSU provides 1500W AC.
If connected to high-line AC power, the PSU in slot PSU1 provides all of the power required by the FortiGate-6000F.
PSU2 and PSU3 are backup power supplies.
Typically, only 2 PSUs, each connected to separate power feeds, are required for full 1+1 power redundancy.

The additional power supply may be connected if there are 3 separate power feeds. 

Applicable for FG-6300F,  FG-6301F,  FG-6500F and  FG-6501F.

Gen1 and Gen2 models can be identified by the part-number as highlighted below.

Product Gen1(System/Module) Gen2(System/Module)
FG-6300F P22350-01 to P22350-05 P22350-06 and above
FG-6301F P22354-01 to P22354-05 P22354-06 and above
FG-6500F P22352-01 to P22352-05 P22352-06 and above
FG-6501F P22356-01 to P22356-05 P22356-06 and above