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If you still own a desktop with an LGA 1155 socket (the square metal bed your processor clicks into), you do not need a whole new computer. You need one part. A single LGA 1155 chip can turn that machine into one that boots in seconds and handles a dozen browser tabs without stutter. The trick is matching the chip to your board’s BIOS support and your workload, not chasing the highest model number.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Every chip here uses the same LGA 1155 socket, so the question is not whether it fits but which one suits your workload. Below you will find the fastest unclocked quad-core, the value hyper-threaded option, and the low-power chips that run nearly silent, all ranked for the cpu for lga 1155 that matches your budget and your board.
Our Picks at a Glance
How To Choose The Best CPU for LGA 1155
You are upgrading an existing machine, not building a new one. That single fact narrows your shopping list to almost nothing. Here is what actually matters when you are picking a chip for a board you already own.
Check your BIOS before you buy anything
A 2nd-generation chip and a 3rd-generation chip share the same physical socket, but your motherboard needs firmware that recognizes the newer one. Most boards from that era shipped with support, but some needed a BIOS update first. The practical move: update your BIOS before the new chip arrives, and keep your old processor on the desk until the new one boots.
Decide if you want the open up “K” version
A “K” at the end of the model number means the chip is open up, so you can raise its clock speed yourself through the motherboard settings. That only pays off if your board has an overclocking chipset and you have a decent aftermarket cooler. If neither is true, a non-K chip gives you the same everyday speed for less.
Match the power draw to your case
The TDP (thermal design power — roughly how much heat the chip throws off) decides how loud your PC gets. A low-wattage chip stays quiet in a small case or a machine left running all night. A higher-wattage one runs faster but wants better airflow.
Quick Comparison
| Model | Best For | Clock Speed | Cores / Threads | Cache | Amazon |
|---|---|---|---|---|---|
| Intel Core i5-3570K★ Best Overall | Gaming and overclocking on a budget | 3.4 GHz | 4 / 4 | 6 MB | Amazon |
| Intel Core i7-3770Top Performer | Multitasking and virtualization | 3.40 GHz | 4 / 4 | 8 MB | Amazon |
| Intel Core i7-3770K | Top raw performance on the socket | 3.5 GHz | 4 / 8 | 8 MB | Amazon |
In‑Depth Reviews
1. Intel Core i5-3570K Quad-Core Processor 3.4 GHz 4 Core LGA 1155 – BX80637I53570K
Our pick — over 4.5★ from 800+ verified ratings; the strongest balance of quality and price.
Four open up cores at 3.4 GHz — the budget pick for gaming on an existing LGA 1155 board.
If your LGA 1155 board is sitting under a coffee-stained case and you just want it to play the games you already own at a smooth frame rate, this is the chip to buy. It runs four physical cores at 3.4 GHz (the base speed it holds without any tweaking), so games and everyday tasks feel responsive. It also carries 6 MB of Intel Smart Cache — a fast on-chip scratchpad that keeps frequently used data close to the cores so the processor is not waiting on your RAM. The 22 nm lithography (how tightly the transistors are packed) is what lets it hold that speed without turning your case into a space heater.
Where this chip separates itself is the open up multiplier, which is the setting that lets you raise the clock speed yourself. The K is the whole point: buyers report reaching 4.5 GHz on a Gigabyte Z77-UD3H and 4.6 GHz on a Corsair H100, with load temperatures staying under 70C on the liquid cooler. Against the Core i5-3470, which is locked and cannot be pushed, this one offers headroom the 3470 simply does not have. It also clocks 6% higher on base speed from the start — 3.4 GHz against the 3470’s 3.20 GHz.
The honest catch is cooling. Amazon’s own read of the reviews flags cooling as the mixed topic here, and the pattern is consistent: the chip itself runs fine, but the bundled stock fan and heatsink are the weak link. Owners mention the stock cooler failing within a day and the stock thermal paste being poor quality, so factor in an aftermarket cooler before you order. Slot it into a Z77 or Q77 board if you want the full feature set, and skip the stock fan entirely.
What It Gets Right
- open up multiplier — customers note pushing it to 4.5 GHz and beyond with a proper cooler
- 3.4 GHz base clock and 6 MB Smart Cache handle CPU-heavy games without stutter
- 22 nm build runs four cores without demanding a huge power supply
- Plays nicely with a wide spread of Z77 and Q77 motherboards
The Honest Caveats
- Overclocked, this chip runs hot — the load temperatures climb fast once you push the clock
- The bundled cooler is the weak point; budget for a better one
- Needs a Z77 or Q77 board to open up the overclocking you are paying for
Pick this if: you game, you want to tune your own clock speed, and you already own or plan to buy a decent cooler.
Think twice if: you are running a locked business board — the K premium buys you nothing there.
2. Intel BX80637I73770 Core i7-3770 3.40 GHz Cache 8MB Processor
Four cores and eight threads at 3.40 GHz — the locked, non-K pick for virtual machines and photo work.
You are the buyer running virtual machines, compiling code, or driving two monitors at once. This chip is built for exactly that. It runs at 3.40 GHz, and its 8 MB of L3 cache (a shared pool of fast memory the cores all dip into) is twice the size of the budget-tier caches in this lineup. The headline feature is Hyper-Threading: four physical cores present themselves to your operating system as eight logical processors, so heavy multi-tab work gets spread across more lanes instead of queuing up.
Owners describe running multiple guest operating systems on Windows 8 with 16GB of RAM without the machine bogging down, and at least one has rigged a Gentoo Linux kernel compile to finish inside six minutes. The stock cooler behaves: idle temperatures sit around 35–45C and the fan is barely audible. On everyday jobs and common tasks the gap in speed against the K-suffix version is not something anyone will notice.
What you give up is tuning. This is the non-K part, so the multiplier is locked and you cannot raise the clock yourself — buyers who want to overclock need the K-series, and the newer i5-3570K retains the open up multiplier this one drops. What you gain instead is eight-thread muscle. If your days are heavy multi-tab multitasking rather than frame-chasing, that trade is a good one.
The real play: Hyper-Threading turns four cores into eight processing lanes, which is why virtualization and photo editing feel so much smoother here than on any four-thread chip on this list.
What you give up: the multiplier is locked, so every bit of speed you get is the speed that came in the box.
Suits you if: your workload is many programs at once, not one fast frame after another.
Walk past if: you want to tune your own clock speed or you are purely gaming on a tight build.
3. Intel Core i7-3770K Quad-Core Processor 3.5 GHz 8 MB Cache LGA 1155 – BX80637I73770K
The fastest LGA 1155 chip — 3.5 GHz, eight threads, and an open up multiplier in one part.
Here is the ceiling of the LGA 1155 platform. Four cores, eight threads (hyper-threading doubles the work lanes your system sees), a 3.5 GHz base clock, and 8 MB of shared L3 cache. It supports 32GB of memory across two channels, which makes the platform feel substantially less like an old machine. If your board takes this chip, it takes nothing better.
The performance story is genuinely strong for a chip this age. Reviewers point out transcoding a one-hour-and-forty-five-minute HD video in roughly eleven minutes at under 20% CPU usage, and others have pushed an overclock to around 5.5 GHz on low voltage. For a socket this old, that is real headroom. Where it dominates is multitasking: heavy work spreads across those eight threads where the four-core, four-thread budget chips have nowhere to push the overflow.
Both this and the i5-3570K share an open up multiplier (a setting that lets you raise the clock speed) and the same HD 4000 integrated graphics, so the real question is if you need hyper-threading (extra processing lanes that let one core handle two tasks at once). If your work is rendering, virtual machines, and transcoding, you do, and this is the chip to buy on this socket. If your work is gaming and browsing, the 3570K saves you bundle and closes most of the gap single-threaded. Budget also matters: there is a meaningful premium here, and you are paying it mostly for those extra threads.
Thread ceiling: hyper-threading is the entire reason to reach past the i5-3570K. Eight lanes versus four is the difference between a machine that shrugs off a video export and one that sits there while it grinds.
Worth knowing: a non-overclocked build lands a Windows Experience Index of 7.7 overall and 7.9 for processor, which tells you the chip is running at the limit of what that old scoring system measured.
Take this one: if rendering, virtual machines, or video work is the point of your machine.
Leave it on the shelf if: gaming is all you do — the i5-3570K gets very close for noticeably less.
4. Intel Core i5-2400S Quad-Core Processor 2.5 GHz 6 MB Cache LGA 1155 – BX80623I52400S
Four cores at 65 W TDP — the low-heat pick for a quiet, always-on desktop.
If your PC lives under a TV, in a bedroom, or in a home office wres here, 8 MB on the i7 parts — and a bigger cache means fewer trips to slower system memory.
TDP and Why It Decides How Loud Your PC Gets
TDP, or thermal design power, is a rough number for how much heat the chip throws off under load. A 65 W chip like the i5-2400S gives off less heat, so its fan spins slowly and quietly and it works in a small case. A 95 W chip like the i7-2600 gives off more, so it wants better airflow. If noise matters to you, the TDP number on the spec sheet is the one to check first.
Why the Socket and BIOS Decide Compatibility
Every chip on this list uses the LGA 1155 socket, so the physical fit is guaranteed. The variable is the BIOS — the firmware that runs before Windows loads. A 3rd-generation chip paired with an older board may need a BIOS update before it is recognized. Update the firmware first, keep your old processor until the new one posts, and you avoid a frustrating no-boot.
FAQ
Will an LGA 1155 CPU fit my old motherboard?
Can I overclock a non-K processor?
Is the i5-3570K better than the i7-3770K for gaming?
How much does hyper-threading actually help?
Do I need a graphics card with these processors?
Which cache size matters more, 6 MB or 8 MB?
Is a low TDP chip worth it for a home theater PC?
What is the difference between a K and a non-K processor?
Will a 3rd-gen CPU work on a 2nd-gen motherboard?
How long do these processors typically last?
Final Thoughts: The Verdict
The cpu for lga 1155 that will make the most people happy is the Intel Core i5-3570K, because it gives you four fast cores, an open up multiplier for tuning, and the best balance of price and performance for gaming and everyday use. If your work leans on multitasking — virtual machines, video, or code — reach for the Intel Core i7-3770K and its eight processing lanes. And if you are upgrading a quiet, always-on machine in a small case, the Intel Core i5-2400S is the low-heat chip to reach for.
One last thought for the undecided: if you are replacing a chip on a board you already own, pick the one that matches what you do most — and if it is mostly office work and older games, start with the i5-3470 and its proven track record of running for years without complaint. Anything else is buying speed you may not need.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of September 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, Gardening Beyond earns from qualifying purchases. This does not affect which products we feature.