Some features not normally used in low latency deployments because of their adverse impact are removed. The following table gives a comparison of features on the X3522 and the X2522 (its predecessor):
| Feature | X2522 | X3522 |
|---|---|---|
| Size | Low-profile, half length | Low-profile, half length |
| Interfaces | 2 SFP+ cages (2×10/25G) | 2 DSFP+ cages (2×2×10/25G) |
| PCIe vendor ID | 1924 (Solarflare) | 10ee (Xilinx) |
| OS support | Linux, Windows, VMWare | Linux |
| Net driver name |
sfc
|
xilinx_efct
|
| Onload support | Yes | Yes |
| TCPDirect support | Yes | Yes |
| ef_vi support | Yes | Yes |
| Sfptpd support | Yes | Yes |
| Oscillator | Discrete Stratum 3 | Discrete Stratum 3 |
| Hardware timestamps | Yes | Yes |
| Jumbo frame support | Yes | No |
| RX queues | Multiple separate queues | Shared queue |
| TX types | DMA, PIO, CTPIO | CTPIO only |
| Number of filters | 16384 total | 512 per port |
| Types of filter | 3 or 5 part IP, MAC address, all-unicast, all-multicast, all-discards | 3-part IP, MAC address+VLAN, all multicast |
| Dropped on NIC | Unsubscribed/unwanted | Explicit only |
| Duplicate multicast filters | Yes | No |
| PF-VLAN | Yes | No |
| Multi-PF mode | Yes | No |
| SR-IOV support | Yes | No |
| Hardware TX checksum offload | Yes | No |