The PCI lanes might be insufficient due to limited slot availability.
The PCI lanes might be insufficient due to limited slot availability.
The only brand that stands out is Gigabyte because we had a really poor experience with their items. He also prefers AMD over Intel, so it seems like he’s leaning toward that direction.
There are 24 PCIe lanes available from the CPU. 16 of these connect to the video card slot, while the motherboard maker can divide them into two sets of eight PCIe x8 slots. Four lanes go to the M.2 connector, and four more to the chipset. The chipsets generate between six and eight PCIe lanes. Typically, four are allocated to the bottom PCIe x16 port, with the remaining lanes distributed across PCIe x1 slots and additional M.2 connectors. The CPU is limited by its socket (AM4) pin count, preventing more than a certain number of lanes. With PCIe 4.0, there are also restrictions on the maximum distance from CPU pins to GPU chips or other components in the slot. The available length is usually around 30-40 cm; if the slot is too short, the manufacturer may need to add amplifiers or repeaters, which increases cost. Some manufacturers use PCIe switch chips that handle 4, 8, or 16 lanes and can rearrange them as needed. However, these are rare and expensive, often matching the price of Threadripper boards. Threadripper processors offer 64 PCIe lanes, leaving 60 available for slots and M.2 connectors. Many boards feature four or five PCIe x16 slots plus two to three M.2 ports.
Exactly... But no motherboards give you 5 PCie Slots we have looked high and low... Why?
Due to physical constraints, these boards would occupy excessive space on the motherboard, complicating the inclusion of m.2 connectors and additional components. Popular IT retailers highlight three models featuring five PCIe x16 slots: x16/x16/x8/x4/x4. The GIGABYTE X299 UD4 PRO and its updated version are notable options. When expanding to around 15–20 models, you’ll find a limited selection locally, and adding a PCIe riser might be necessary for a fifth card, though this would reduce performance in that slot. Other brands like ASRock, ASUS, and GIGABYTE also offer similar configurations, but none are recommended for purchase at the moment. Both chipset lines (x299 and x399) are considered outdated, with newer Threadripper variants supporting different sockets and Intel’s socket 2066 being obsolete.
Well if he wants AMD, like i said there's x399 ... for the older Threadripper. Yes, there's more x299 boards for socket 2066, but they're not all x16 slots, they're mostly x16 and the rest x8 or x4, because there's not enough pci-e lanes on x299 boards. On the latest threadripper boards you have boards like GIGABYTE TRX40 AORUS PRO WIFI or GIGABYTE TRX40 DESIGNARE with 4 pci-e x16 ( 2x16 and 2x8) and one pci-e x1 slot .... also they're all pci-e 4.0, so a pci-e 4.0 x8 is prety much equivalent to pci-e 3.0 x16 One more thing I forgot about why not 5 or more pci-e x16 slots - because most people that would buy such expensive boards would buy powerful video cards that take up 2-3 slots, so the room below the first pci-e slot will usually be used for other things like m.2 connector or extra controllers. You can check out that TRX40 designare to see what i mean, those 4 pci-e slots are perfectly spaced, so you could install 4 double slot video cards.
Thanks for the details. However, the idea that he needs at least four x16 slots isn't accurate. He doesn't mind using x8 slots; it's just not suitable for x4 configurations since his add-in cards are long (like 4-port Nic cards and GPUs). For GPUs, one x16 slot connects to a main monitor (2x4K) and a dedicated GPU for always-on-screen at 960p. Whether it's running in x8 or more doesn't matter—what matters is the ports he needs. If he upgrades later with boards that lack slots, he won't be able to use all his cards. So he's really stuck.
Unless those are 10gbps connections, the card should function in a x1 slot, though x2 or x4 would be better options. A port delivering 1 gbps equals 125 MB/s, so four ports could reach up to 500 MB/s via PCIe 2.0 x1. PCIe 3.0 x1 offers up to 970 MB/s, while a real-world scenario typically delivers around 480 MB/s or more after accounting for overheads. If the chip is older and only supports PCIe 2.0 on its four ports, using at least PCIe x2 makes sense, but PCIe x1 would still be viable since not all ports will operate at full capacity simultaneously. Four 10g ports would require about 5 GB/s, which matches roughly six PCIe lanes (6 × 970 = 5820 MB/s), but a four PCIe 3.0 ports setup (~3.8 GB/s) would suffice if not all ports are active at once.