The b850 has finally hit the market, and it’s now available for purchase. But does it bring a meaningful upgrade compared to its predecessor, the b650? A glance at AMD’s official specs provides clarity. However, there seems to be some confusion regarding the PCIe 5.0 capabilities of the b850—it shouldn’t just be limited to 4×5.
0. In reality, the b850 supports a PCIe 5.0 graphics card and one PCIe 5.0 M.2 slot, with USB 4.0 still being optional. On the other hand, the b650 accommodates a PCIe 4.0 graphics card and one PCIe 5.0 M.2 slot. The standout advancement here is the introduction of a 5.0 interface for the graphics card.
With the launch of the nv50 series of graphics cards, it’s been confirmed that all models from the 5070 upwards feature upgraded 5.0 interfaces across the board. By equipping the b850 with a PCIe 5.0 slot for the graphics card, AMD aligns itself perfectly with the evolving demands of modern hardware.
Beyond the chipset itself, much depends on how motherboard manufacturers choose to design their layouts. Take the ASUS TUF 850 Heavy Gunner as an example—whether you’re looking at mATX or ATX formats, the graphics card slot is now 5.0, and there are three M.2 slots in total. One of these M.2 slots connects directly to the CPU via PCIe 5.
0, while the other two utilize PCIe 4.0 through the southbridge. Notably, the ATX variant retains the lower PCIe slot, whereas the mATX version omits it. This omission could potentially cause conflicts with the second and third M.2 slots due to the southbridge’s limited total bandwidth of 4.0×4.
Shifting focus back to the comparison between the b850 and b650, let’s examine the ASUS 650m and 850m Heavy Gunners. Ignoring differences in the graphics card interface, the b850 removes the lower PCIe slot and adds an extra M.2 slot. Personally, I find this to be a practical enhancement. With three M.2 slots, the b850 sidesteps potential issues where the graphics card might obstruct installation, thus enhancing both convenience and flexibility.
In conclusion, the specification gap between the two chipsets isn’t monumental; the b850 primarily introduces a 5.0 interface for the graphics card. However, the actual motherboard layout can provide additional benefits. From my perspective, there is indeed an improvement, albeit not a game-changing one. Fortunately, the price remains competitive, showing little increase compared to the b650.
Zachary Ruiz 
Miles Holt 
Paul Miller
I see the B850 offers some nice upgrades like full PCIe 5.0 support, but I’m still on the fence since my current setup with B650 is working fine. It really depends on whether I need those extra features or if they’ll future-proof my build enough to make it worth it. The optional USB 4.0 is intriguing, but I wish AMD clarified that earlier. Guess I’ll wait and see what benchmarks say before pulling the trigger.
You’re absolutely right to weigh the benefits carefully! While PCIe 5.0 and USB 4.0 are exciting, they may not be essential depending on your current needs. It’s smart to wait for benchmarks—those will give you a clearer picture of the real-world performance gains. Thanks for sharing your thoughts; it’s always helpful to hear balanced perspectives like yours!