B450 is a mainstream AM4 chipset that launched in 2018 for the Ryzen 2000 generation of processors. It allows CPU overclocking and has the widest processor support of any AM4 chipset still commonly sold: Ryzen 1000 to Ryzen 5000, the last of those after a BIOS update. Its limit is PCIe 3.0. It is the oldest chipset we track for AMD, so this guide is mostly about whether buying one still makes sense. Current offers are on the B450 deals page.
Cheapest B450 boards right now
All 11 B450 motherboards, with price drops and price history
Where B450 sits
B450 was the mainstream chipset of the second AM4 generation, below X470. It was succeeded by B550 in 2020, and AM4 as a whole was replaced by AM5 in 2022. B450 stayed on sale for a long time because it was inexpensive and AMD extended its processor support further than first planned.
Key specifications
| Feature | B450 | B550 | A520 |
|---|---|---|---|
| Launched | 2018 | 2020 | 2020 |
| CPU overclocking | Yes | Yes | No |
| Graphics slot and main M.2 (from the CPU) | PCIe 3.0 | PCIe 4.0 | PCIe 3.0 |
| Chipset lanes | PCIe 2.0 | PCIe 3.0 | PCIe 3.0 |
| Ryzen 1000 and 2000 | Yes | No | No |
| Ryzen 5000 | Yes, after a BIOS update | Yes, early boards may need an update | Yes, early boards may need an update |
B450 boards run at PCIe 3.0 even with a Ryzen 3000 or 5000 processor that supports PCIe 4.0. The chipset's own lanes are PCIe 2.0, so a second M.2 slot or an add-in card connected through the chipset is noticeably slower than the main slot. Put your main SSD in the M.2 slot that connects to the processor; the manual says which one that is.
Compatible CPUs
With the right BIOS, B450 supports Ryzen 1000, 2000, 3000 and 5000 desktop processors, and the G-series chips with integrated graphics from the 2000G parts through to 5000G. Exactly which are supported depends on the board and its BIOS version, so check the board's CPU support list on the maker's website.
Two BIOS points matter more on B450 than on any other chipset:
- Ryzen 5000 needs an update. B450 boards were designed two processor generations earlier. AMD and the board makers added Ryzen 5000 support through BIOS updates from around the start of 2021. A board with an older BIOS will not start with a Ryzen 5000 chip. Without a BIOS flashback button, you would need an older supported processor fitted to carry out the update.
- Updates can remove older chips. The BIOS storage on many B450 boards is too small to hold support for every AM4 processor. On a number of boards, the BIOS versions that add Ryzen 5000 drop support for some of the oldest chips. Read the notes for each BIOS version before updating if you still own an early processor.
Some makers released refreshed B450 boards, such as MSI's MAX models, that shipped ready for Ryzen 3000. Those still need a late enough BIOS for Ryzen 5000. The full procedure is in BIOS updates and CPU compatibility.
Memory
B450 uses DDR4 only. XMP profiles are supported, labelled DOCP or A-XMP by some makers. Ryzen 3000 and 5000 processors generally do best with DDR4 at 3200 to 3600 MT/s. With Ryzen 1000 and 2000 chips, fast memory kits are less likely to run at their rated speed, and older boards tend to be fussier about memory than B550 ones.
B450 against B550 and A520
B550 gives the graphics slot and main SSD PCIe 4.0, has PCIe 3.0 chipset lanes, and its boards are newer designs with better power delivery on average. It does not support Ryzen 1000 or 2000, or the 3200G and 3400G. If your processor is Ryzen 3000 or newer and the price gap is modest, B550 is the better board to buy.
A520 is newer but cannot overclock the CPU, and it has the same processor restrictions as B550. Against A520, B450 offers overclocking and support for older chips; A520 offers a newer design and faster chipset lanes.
Whether B450 is still worth buying
As the base for a new build, no. A design from 2018, on a socket replaced in 2022, limited to PCIe 3.0 and DDR4, is the wrong place to start. AM5 vs AM4 explains where to start instead.
B450 does still make sense in three situations:
- Your board has failed and you own a Ryzen 1000 or 2000 processor, or a 3200G or 3400G, that the newer AM4 chipsets will not run.
- You want the least expensive route to keeping an existing AM4 processor and DDR4 memory in service.
- You are building a second or family PC from spare parts.
In all three, paying full price for new stock of so old a design is poor value, which makes reduced and opened-box boards the natural choice. AM4 works in favour of that: the pins are on the processor, not in the board's socket, so the socket is harder to damage than on AM5 or Intel boards. Do check the rest of the board using our used motherboard checklist.
What varies by board
- Power delivery. Many B450 boards were built for six- and eight-core chips of 2018. For a Ryzen 9 5900X or 5950X, choose a board with substantial heatsinks over its power delivery and confirm the chip is on its support list.
- BIOS flashback. Present on some boards, absent on many.
- M.2 slots: one or two, and the second is often slower.
- WiFi: uncommon, and WiFi 5 where fitted on most models.
- Size: ATX, micro-ATX and mini-ITX boards were made.
What to check on the listing
- Your exact processor on the board's CPU support list, and the BIOS version it needs.
- Whether the board has a BIOS flashback button.
- The model revision: MAX, II or V2 versions differ from the originals.
- The price of the nearest B550 board.
Current reductions are on the B450 deals list, and opened-box stock is on the Warehouse page.
Questions people ask
Does B450 support Ryzen 5000 processors?
Yes, after a BIOS update. B450 gained Ryzen 5000 support through BIOS versions released from around the start of 2021. A board with an older BIOS will not start with a Ryzen 5000 chip until it is updated.
Does B450 support PCIe 4.0?
No. B450 boards run the graphics slot and main M.2 slot at PCIe 3.0, even with a processor that supports PCIe 4.0. The chipset lanes are PCIe 2.0.
Can I update a B450 BIOS without an older CPU?
Only if the board has a BIOS flashback feature, which updates from a USB stick with no processor fitted. Many B450 boards do not have it, so check before buying one for a Ryzen 5000 chip.
Can you overclock on B450?
Yes. B450 allows CPU and memory overclocking. How far you get depends on the power delivery of the board.
Is B450 or B550 better for a Ryzen 5 5600?
B550. It supports the chip with less chance of needing a BIOS update, and it gives the graphics card and main SSD PCIe 4.0. B450 will run the processor at the same speed once its BIOS is up to date.