I'm considering a build with the 9950X3D and a 5090 GPU, and I'm torn between three motherboards: the B850-P, X870P, and X870E. Are they pretty much on par in terms of performance, or does one stand out for my setup? If they perform similarly, I'm inclined to go with the more affordable option.
Also, I came across the term 'lane sharing' and was wondering if it applies to any of these boards. Should I worry about this feature and its implications for my future upgrades?
2 Answers
In terms of performance, going from 16x to 8x usually only results in about a 1% drop, so it's not a huge concern. But since you can avoid the lane sharing issue with the B850, it’s a solid choice for a smoother experience, especially if you're looking to save money.
Most of the X870 and X870E boards have an issue with lane sharing, where the first PCIe 16x slot can drop to 8x if you install an M.2 SSD in certain slots. For instance, on the Gigabyte X870E Aorus Pro Ice, if you put SSDs in the second or third M.2 slot, the main PCIe lane works at 8x instead of 16x. There are some X870E boards that avoid this problem, but you'll need to research them. On the flip side, B850 boards don't have this issue because they skip USB4 support, freeing up more PCIe lanes. If you go with the B850, you'll have fewer worries about lane sharing.
Got it, so if I stick to one SSD in the first slot, I should be fine with the GPU not sharing lanes?
Exactly! Just make sure you manage the installation correctly.
Thanks for confirming! I think I’ll lean towards the B850 then.