7 Best AM3+ CPUs in 2026: FX Upgrade Buying Guide

The AM3+ socket is long discontinued — AMD's last FX processors arrived over a decade ago, and Ryzen replaced the whole platform years back. So who still buys an AM3+ CPU in 2026? Two groups: people who already own an AM3+ motherboard (the 970, 990X, and 990FX chipsets) and want to squeeze more life out of it without a full rebuild, and budget or retro builders picking up cheap used parts.

If that's you, the good news is that a used AM3+ chip costs very little now, and the fastest of them can still handle everyday computing, light gaming, and older titles perfectly well. The important thing to understand going in: these "8-core" FX chips use AMD's module design, where pairs of cores share resources, so real-world performance sits below what the core count suggests — and well below any modern budget CPU. Set expectations accordingly, and an AM3+ upgrade is a sensible, low-cost move.

Because the socket is retired, most of these chips are only sold used or renewed now, and individual listings come and go. Each pick below links to a current Amazon search for that exact model so you always see whatever stock is actually available.

Quick comparison

CPU	Best for	Cores / Threads	Base / Max clock	TDP
AMD FX-8350	Best overall value	8 / 8	4.0 / 4.2 GHz	125 W
AMD FX-8370	Best 8-core (with cooler)	8 / 8	4.0 / 4.3 GHz	125 W
AMD FX-9590	Most powerful AM3+ chip	8 / 8	4.7 / 5.0 GHz	220 W
AMD FX-8300	Most efficient 8-core	8 / 8	3.3 / 4.2 GHz	95 W
AMD FX-6300	Best budget pick	6 / 6	3.5 / 4.1 GHz	95 W
AMD FX-4300	Cheapest entry point	4 / 4	3.8 / 4.0 GHz	95 W
AMD Phenom II X4 945	Older AM3 boards	4 / 4	3.0 GHz	95/125 W

How we picked

We ranked these on the things that actually matter for an aging AM3+ platform: real performance for the money, thermals and power draw (some FX chips run very hot), motherboard compatibility, and how easy the CPU is to find on the used market today. We favored the Vishera (Piledriver) generation over the older Bulldozer chips, since Vishera runs cooler and faster per clock, and we cross-checked current availability so you're not chasing parts that no longer exist. A note on honesty: we haven't bench-tested every chip on a bench in 2026 — these rankings draw on each CPU's documented specifications and their long, well-established track record on the AM3+ platform.

1. AMD FX-8350 — best overall value

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The FX-8350 is the chip most people should get. It's an 8-core Vishera part running at a 4.0 GHz base and 4.2 GHz boost, with 8 MB of L3 cache, and it strikes the best balance of performance, price, and availability in the AM3+ lineup. It's fully unlocked, so if your motherboard and cooling allow it, you can push clocks higher with AMD's OverDrive utility.

For general use, multitasking, and older or less demanding games, it has plenty of headroom, and it pairs well with a mid-range GPU without bottlenecking as badly as the lower FX chips. The one catch is heat: at 125 W it runs warm, and it runs warmer still when overclocked, so a decent aftermarket cooler is money well spent.

Pros

• Best price-to-performance in the AM3+ range
• 8 cores handle multitasking and light content work
• Fully unlocked for overclocking
• Easy to find used

Cons

• 125 W TDP runs hot; wants a good cooler
• Weak single-thread performance by modern standards

Best for: the default choice for anyone upgrading an existing AM3+ board.

2. AMD FX-8370 — best 8-core, ships with a cooler

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The FX-8370 is a slightly higher-binned sibling of the FX-8350: same 8 cores and 8 MB L3, but a marginally higher 4.3 GHz boost, and it originally shipped with AMD's Wraith cooler — a quiet, capable stock heatsink that's a genuine plus if a used unit still includes it. In practice it performs a hair above the FX-8350.

You're paying for a small clock bump and that cooler, so it's worth it only if the price is close to the FX-8350's. If it costs meaningfully more, the FX-8350 is the smarter buy.

Pros

• Slightly faster than the FX-8350
• Often bundled with the quiet Wraith cooler
• Unlocked multiplier for overclocking

Cons

• Same 125 W thermals
• Small real-world gain over the cheaper FX-8350

Best for: buyers who find one near the FX-8350's price, ideally with the cooler included.

3. AMD FX-9590 — the most powerful AM3+ CPU

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If you want the outright fastest chip the socket ever produced, it's the FX-9590. This 8-core Vishera part clocks at an enormous 4.7 GHz base and up to 5.0 GHz boost straight out of the box — no overclocking required. That performance comes at a serious cost, though: a 220 W TDP that demands a robust 990FX motherboard with strong VRMs and, realistically, liquid cooling to keep it stable.

It's the enthusiast's pick, not the sensible one. Don't drop it into a budget board — it can overwhelm weaker power delivery. But on the right platform, it's as fast as AM3+ gets.

Pros

• Highest clock speeds of any AM3+ CPU
• 5.0 GHz boost with no overclocking
• Genuinely fast for the platform

Cons

• 220 W TDP; needs liquid cooling
• Requires a high-end 990FX board with strong VRMs
• Power-hungry and hot

Best for: enthusiasts running a high-end 990FX board with proper cooling.

4. AMD FX-8300 — most efficient 8-core

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The FX-8300 is the quiet value play. It's the same 8-core Vishera design but rated at just 95 W, with a 3.3 GHz base and 4.2 GHz boost. You give up some base clock versus the FX-8350, but the lower power draw means less heat, less noise, and easier compatibility with modest motherboards and coolers — a good fit if your AM3+ board isn't a top-tier 990FX.

Pros

• 95 W — cooler and quieter than the 125 W chips
• Full 8 cores and 8 MB L3
• Kinder to lower-end motherboards

Cons

• Lower base clock than the FX-8350
• Can be harder to find than the FX-8350

Best for: builders who want 8 cores without the heat and power of the 125 W parts.

5. AMD FX-6300 — best budget pick

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For years the FX-6300 was the budget king of the AM3+ platform, and on the used market it still makes a lot of sense. It's a 6-core Vishera chip at 3.5 GHz base and 4.1 GHz boost with 8 MB of L3, rated at a manageable 95 W. Six cores is plenty for everyday computing and older games, and because it runs cooler than the 8-core parts, it's an easy, cheap upgrade that leaves budget for a better GPU.

Pros

• Very cheap used, great value
• 95 W — runs cool, easy to cool
• Unlocked for overclocking
• Six cores cover everyday tasks and older games

Cons

• Fewer cores than the FX-83xx chips
• Weak single-thread performance by today's standards

Best for: budget upgrades where you want to spend the savings on a GPU instead.

6. AMD FX-4300 — cheapest entry point

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The FX-4300 is the entry-level Vishera quad-core: 3.8 GHz base, 4.0 GHz boost, 4 MB L3, and a 95 W rating. It's the least expensive way to get a working, overclockable FX chip into an AM3+ board, and for light office work, web browsing, and undemanding games it does the job. Under heavier multitasking it runs out of steam faster than the 6- and 8-core chips, so treat it as a basic-use or last-resort option.

Pros

• Cheapest FX option
• Runs cool at 95 W
• Unlocked multiplier

Cons

• Only 4 cores; struggles under heavy load
• Small 4 MB L3 cache

Best for: the tightest budgets and light, everyday workloads.

7. AMD Phenom II X4 945 — for older AM3 boards

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Strictly speaking the Phenom II X4 945 is an AM3 chip, not AM3+, but it drops into many AM3+ boards (and its AM3 socket accepts the AM3+ chips above, given a BIOS update). It's a pre-Bulldozer 4-core running at 3.0 GHz with 6 MB of L3 cache, and it's a reasonable option if you have an older AM3/AM3+ board that doesn't play nicely with the FX chips, or if you find one for next to nothing. Don't expect FX-level multitasking, but it's a dependable, low-cost quad-core.

Pros

• Works in many AM3 and AM3+ boards
• Solid 6 MB L3 cache for a quad-core
• Extremely cheap used

Cons

• Older architecture; slower than the FX chips
• Not a true AM3+ part

Best for: older AM3-era boards, or as a rock-bottom-budget quad-core.

What to look for before buying an AM3+ CPU

Check motherboard compatibility first. Not every AM3+ board supports every FX chip. The high-TDP parts — especially the 220 W FX-9590 and, to a lesser extent, the 125 W FX-83xx chips — need a board with strong VRMs (a 990FX is safest) and an up-to-date BIOS. Look up your exact board's CPU support list before buying.

Plan your cooling. The 95 W chips (FX-8300, FX-6300, FX-4300) are happy on a decent air cooler. The 125 W FX-8350/8370 want a good aftermarket cooler. The FX-9590 realistically needs liquid cooling.

Remember it's DDR3. AM3+ boards use DDR3 memory, officially up to DDR3-1866. If you're reusing an old build, your existing RAM likely already fits; if you're buying, DDR3 is cheap on the used market.

Buy used, and buy smart. New AM3+ stock is essentially gone, so you'll be shopping used or renewed. Favor sellers with returns, and inspect photos for bent pins — these are pin-grid chips and bent pins are the most common fault.

Be realistic about performance. Even the FX-9590 trails a modern entry-level CPU. An AM3+ upgrade is about cheaply extending a platform you already own, not building something competitive with current hardware.

Frequently asked questions

What is the most powerful AM3+ CPU? The AMD FX-9590. It boosts up to 5.0 GHz out of the box — the highest clock of any AM3+ chip — but its 220 W TDP means it needs a high-end 990FX motherboard and liquid cooling. For most people the FX-8350 is the more practical "best" pick.

Is AM3+ still worth it in 2026? Only if you already own an AM3+ (or compatible AM3) motherboard. As a cheap upgrade to an existing FX build it's a sensible, low-cost move. It is not worth buying a whole AM3+ platform from scratch today — a modern budget CPU will outperform any FX chip for similar money.

Will an AM3 CPU like the Phenom II work in an AM3+ motherboard? Usually yes — AM3+ boards are generally backward-compatible with AM3 chips, and many AM3 boards accept AM3+ FX chips after a BIOS update. Always confirm against your specific board's CPU support list first.

Do I need a special motherboard for the FX-9590? Yes. Because of its 220 W power draw, the FX-9590 should only go into a high-end board (typically 990FX) with strong power delivery, paired with liquid cooling. Weaker boards can't supply it safely.

How much RAM do AM3+ CPUs support? They use DDR3, with official support up to DDR3-1866. Most AM3+ boards take up to 32 GB across four slots, though the exact limit depends on the motherboard.

Final words

For nearly everyone upgrading an AM3+ system, the AMD FX-8350 is the chip to get: eight cores, strong clocks, wide availability, and the best value on the platform. If you want to run cooler and quieter, the 95 W FX-8300 or 6-core FX-6300 are excellent budget choices. And if you have a high-end 990FX board and proper cooling, the FX-9590 is the fastest send-off the socket ever got.

Whichever you choose, pair it with an adequate cooler and a good power supply, and your aging AM3+ rig has plenty of everyday life left in it.