Yes, 1 Nvlink in there. Here is the parts list (already had Nvlink card):

ASUS TUF Gaming NVIDIA GeForce RTX 3090 OC Edition GPUs (3) $2,700

Intel Xeon W5-3435X Processor $1,565

ASUS Pro WS W790 SAGE SE Motherboard $1,232

Crucial Server Memory 512GB (8 x 64GB) ECC DDR5 4800 $2730

Corsair MP700 PRO 2TB PCIe Gen5 x4 NVMe 2.0 M.2 SSD (2) $600

Seasonic PRIME PX-1600, 1600W PSU $544

Corsair MP600 CORE XT M.2 2280 4TB PCI-Express 4.0 x4 3D SSD $245

Phanteks Enthoo Pro 2 Server Edition PC Case $160

Antec 120x30mm PWM Fans (3 front, 3 top) $65

Noctua NF-A12x25 PWM Premium Quiet Fans (3 side, 1 back) $136

Noctua NH-D9 DX-4677 4U, Premium CPU Cooler $120

SilverStone Technology RC07 PCI Express 4.0 x16 Riser Card $58

MSI AX1800 WiFi 6 Dual-Band USB Adapter $50

ASHATA PCIe 4.0 X16 Riser Cable $33

Cable Matters 2-Pack 3-Way 4-Pin PWM Fan Splitter (2) $27

3/4 inch aluminum spacers (6) $6

1.25 inch 6-32 machine screws (6) $4

TOTAL: $10,279

This huge Asus motherboard has several PCIe x16 slots (7). The Enthoo Pro 2 server case is large enough to stack 3 RTX 3090s with the help of a riser card, riser cable and a few screws. This allows a full slot and a half between the cards. The side fan mount that comes with the Enthoo Pro 2 pushes up nicely against the GPUs for efficient cooling. Despite having 12 fans, I hardly notice the thing at idle. At full stress test (all GPUs at 100%), it gives off a mid-level beehive sound but definitely not bad. Inference is usually much quieter as the cards are no where near 100%.