Which is better for 1440p gaming?

The Stormcraft Sirius. The RTX 5070 is the faster card, and DDR5 memory helps in CPU-heavy titles. The Pilum's RTX 5060 is better suited to 1080p.

Which has the better processor?

They trade blows. The Ryzen 7 5700X has 8 full cores for multitasking; the i5-14400F has 10 cores split between performance and efficiency and is newer.

Do I need to add a Wi-Fi card to the Sirius?

Only if you cannot use Ethernet. The Pilum lists Wi-Fi 6E and Bluetooth; the Sirius listing shows no wireless, so budget for a card or adapter.

Which is easier to upgrade later?

The Sirius. Its B760 board uses current Intel CPUs and DDR5, while the Pilum's AM4 socket and DDR4 memory are at the end of their upgrade path.

Is the Pilum worth stepping up to over the Sirius?

Only if wireless and core count matter more than graphics. For raw gaming performance the Sirius is the higher tier.

Stormcraft Sirius Gaming PC vs Velztorm Pilum Gaming Desktop

The Stormcraft Sirius is the stronger gaming machine: its RTX 5070 and DDR5 memory put it a clear step ahead of the Velztorm Pilum's RTX 5060 and DDR4. The Pilum counters with a Ryzen 7 5700X, 8 cores and Wi-Fi 6E built in, which suits multitasking and cable-free setups. Buy the Sirius for frame rates and a newer platform; buy the Pilum if you want more CPU cores and wireless out of the box.

Choose the Stormcraft Sirius if you want the faster graphics card and newer DDR5 memory for high-refresh gaming.
Choose the Velztorm Pilum if you want eight CPU cores and built-in Wi-Fi 6E without adding a card.

Prices

Stormcraft Sirius Gaming PC: $1,049.99 at Newegg (last seen Nov 10)
Velztorm Pilum Gaming Desktop: $1,299.99 at Best Buy (last seen Nov 10)
Difference: the Stormcraft Sirius Gaming PC is $250.00 cheaper than the Velztorm Pilum Gaming Desktop at the latest prices (Nov 10)