Vulkan helps with speed. Must benchmarks prove that out. Concurrency is a mixed bag. You can get some with llama.cpp bit vllm is concurrency king.

Just a couple of weeks ago llama.cpp released tensor parallelism which helps, but its still a experimental feature.

Unfortunately, I don’t know of any diffusion runners that work in vulkan. If someone has expertise, let me know!

This is something I learned the hard way.

Consumer hardware is limited by multiple factors when it comes to PCIe connectivity.

• Physical layout. Easy how many slots you have to plu into, their size, and configuration.
• Supported lanes from the CPU
• chipset (motherboard) limitations

Your graphics card might be a 16 lane card (referred to as “x16”), but sometimes, not all of them are used. Aforementioned 5060ti - I believe only uses x8. Some devices like graphics cards can use a physically smaller slot with an adapter for a loss in performance (a few frames in game play performance)

Similarly, your motherboard might have a x16 slot and another x16 at the bottom. That second slot might only function as x8 or even x4. Does this matter? Sort of. Inta-card communication aka peer to peer communication can affect affect performance and that can compound with multiple cards.

Even worse, some motherboards may have all sorts of connectivity but may have limitations like only 2 out of the bottom 4 slots, PCIe and m.2, can work at a time. ASK ME HOW I KNOW.

Your CPU controls PCIe. It has a hard cap in how many PCIe devices it can handle and what speed. AMD tends to be better here.

Enterprise gear suffers from none of this bs. Enterprise CPUs have a ton of PCIe lanes and enterprise motherboards usually match the physical size of their PCIe slots to their capacity and support full bifurcation*

PCIe lanes are used up by and consumable by m.2, MCIO, and occulink to name a few. That means that you can connect a graphics card to either one is those of you can figure out the wires and power**

• ** Bonus: bifurcation and how my $200 consumer motherboard runs 6 graphics cards.

Bifurcation is a motherboard feature that lets you split PCIe capacity, so a 16x slot can support two x8 devices. My motherboard lets me do this on just the main slot and in a strange x8x4x4 configuration. I have an MCIO adapter (google it) which plugs into the PCIe and gives me 3 PCIe adapters with those corresponding speeds.

it also has 2 m.2 slots which connect to the CPU. One is them, I use for a nvme ssd like a normal person. The other is an m.2 to PCIe adapter which gives me an x4 PCIe slot. For those keeping track, that’s 24 PCIe lanes so far. That’s the maximum my processor Intel 265k can handle

But wait! The motherboard also has a kind of PCIe router and that thing can handle 8 more lanes! So I use the bottom 2 PCIe lanes on my motherboard for 2 cards at x4 each. The thing that kills me is that there are more m.2 ports. But the mobo will not be able to use any more than 2 devices at once. AND even though that bottom PCIe slot is sized at x16, electrically, its x4.

Do your research (level1techs is great) and read the manuals to really understand this stuff before you buy

My mobo for reference ASUS: TUF GAMING Z890-PRO WIFI

It matters a bit but not as much as you’d think, it also depends on what model and what runner you’re using I think. There’s a lot of optimizing that can be done, but in practice, you’re not going to notice huge difference in speed. Again, remember that these are not speed-demon cards to begin with, the main feature is the large VRAM capacity that allows them to run very large, powerful models without the speed penalty of dropping to system RAM, and that, at least where I understand it, is where the PCIe starts to matter a lot more. That said, maybe I’m wrong. I’m not an expert at this stuff and my experience is limited to what little hardware in what limited configurations I have available personally. Best of luck in your adventures, anything we can do to democratize machine learning technology to more people is worth pursuing I think.