No, A520 boards are designed for a single GPU.
No, A520 boards are designed for a single GPU.
You're looking into compatibility and performance details for ASRock A520 boards. The A520 supports multiple x16 slots, including dual PCIe 3.0 slots, though the second one operates at half speed. For your questions: running two GPUs on PCIe 3.0 x16 should work, but expect reduced performance on PCIe 2.0 x16. Regarding GPU choices in a budget build without B550 or better, the A520 chipset is generally sufficient, while the B450 offers more options but at a higher cost.
Creating a budget with multiple GPUs is useful for maximizing performance and cost efficiency.
Why not? For fun, to mess around with some hardware laying around currently unused. To try and get lossless scaling working on a separate GPU. To have some fun. I already have everything else, except the motherboard with multiple PCIe x16 slots, and a cheap one would provide a cheap way to tinker with some stuff. Buying a more expensive board would be less sensible for such a use case. Or I guess technically I could buy a cheaper B550 board if it would be significantly better option than A520 and B450.
The process isn't straightforward because modifying a slot on your existing board is questionable. Purchasing an entire board for experimentation appears unreasonable.
I own everything except a functional motherboard. I plan to purchase a budget new board regardless; the extra x16 slot is appealing. If it doesn’t fit well, at least I’m trying something different. I’ve heard that the A520 can’t handle multiple GPUs at the chipset level, though I’m not certain. The B450 should accommodate a second GPU, but cheaper models often use PCIe 2.0 rather than 3.0 on the second slot—this might not be significant if it won’t run a high-end PCIe 4.0 GPU, but it could still matter.
The second position supports PCIe x2 irrespective of the generation, meaning a PCIe gen 2 card will operate as PCIe 2.0 x2 there. It makes sense to swap out the main GPU for an older one if you prefer. I've noticed mining boards using A320 chipsets that are quite similar to A520, handling multiple GPUs simultaneously, though not all at once. The idea of combining multiple GPUs might be related to DX12's multiGPU feature.
The PCIe lane count is determined by the processor and then the chipset adds a few more. The initial PCIe x16 port receives lanes from the CPU. A520 boards keep these 8 or 16 lanes in one slot without splitting them, while very few Athlon CPUs use just 4. The remaining slots get lanes created by the chipset—typically between 4 and 6, unless two SATA ports are disabled. Consequently, video cards can fit in those slots but only have up to 4 lanes, whereas a Pro4 supports two lanes.
It relies on whether your GPUs have low clearance and if the top one fits over the other. A common guideline is to use an ATX motherboard. Alternatively, choose a board with additional slots that aren't obstructed.