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Intel Pentium G840

Intel Pentium G840: A Comprehensive Review of an Obsolete Processor in 2025

Introduction

The Intel Pentium G840, released in 2011, became part of the Sandy Bridge architecture era. Despite its venerable age, it is still found in budget PCs and systems from "the past." In this article, we will analyze its relevance in 2025, the tasks it can handle, and who should pay attention to it.

Key Specifications: Sandy Bridge and Modest Performance

Architecture and Process Technology

The Pentium G840 is built on the Sandy Bridge microarchitecture (32 nm), which at the time brought improvements in energy efficiency and IPC (instructions per clock). It is a dual-core processor without Hyper-Threading support (2 cores / 2 threads), with a base frequency of 2.8 GHz. It features a 3 MB L3 cache and an integrated Intel HD Graphics core (6 Execution Units).

Performance

According to Geekbench 6:

- Single-Core: 457 points — comparable to modern ARM processors for smartphones.

- Multi-Core: 782 points — on par with budget chips from 2018–2020 (e.g., Intel Celeron G4900).

Key Features

- Supports SSE4.1/4.2 instructions, but lacks AVX (important for modern AI/rendering tasks).

- TDP of 65 W: low power consumption for basic tasks.

- Integrated graphics: suitable for video output but not for gaming.

Compatible Motherboards: Hunting for Rarities

Socket and Chipsets

The processor uses the LGA 1155 socket. Compatible chipsets include:

- H61, B65, H67, Q67, P67, Z68.

- It is recommended to look for motherboards with SATA III (6 Gbit/s) and USB 3.0 support (e.g., ASUS P8H61-M LE).

Selection Considerations in 2025

New motherboards for LGA 1155 are no longer produced. Prices in the secondary market range from $20 to $50 (e.g., used ASRock H61M-DGS). Check the condition of capacitors and the presence of updated BIOS to avoid boot issues.

Supported Memory: Only DDR3

The Pentium G840 works with DDR3 memory (up to 1333 MHz). The supported memory capacity depends on the motherboard (usually up to 16–32 GB).

- Important: DDR4 and DDR5 are not compatible!

- It is recommended to use dual-channel mode (2 modules of 4 GB each) to boost integrated graphics performance.

Power Supply: Minimal Cost

With a TDP of 65 W and no discrete graphics card, a power supply of 300–400 W is sufficient (e.g., be quiet! System Power 10 400W, $45).

- If planning to install a GPU (e.g., NVIDIA GT 1030), choose a PSU of 450 W with an 80+ Bronze certification.

- For systems without upgrades, even a noname PSU can suffice, but this is risky — better not to skimp.

Pros and Cons: Weighing the Arguments

Pros

- Energy Efficiency: Suitable for 24/7 PCs (e.g., media server).

- Price: on the secondary market — $5–15 (in 2025).

- Reliability: a time-tested architecture.

Cons

- Weak Performance: cannot handle modern OS (Windows 11 is officially unsupported).

- Limited Multitasking: 2 threads are insufficient even for a browser with 10 tabs open.

- Outdated Technologies: lacks USB 3.1, NVMe, HDMI 2.0.

Usage Scenarios: Where the G840 Still Holds Up

1. Office Tasks: Word, Excel, email — but only if SSD and 8 GB of RAM are used.

2. Media Center: Playback of Full HD video via VLC or Kodi (4K not supported).

3. Server Tasks: File storage, print server based on Linux.

4. Retro Gaming: games from the 2000s (e.g., Half-Life 2, GTA: San Andreas) on low settings.

Practical Example:

A user assembled a PC with G840 + 8 GB DDR3 + 240 GB SSD for their parents. The system runs on Linux Mint, launches a browser, and plays YouTube videos (1080p). Problems began when attempting to watch streams on Twitch (lag due to insufficient power).

Comparison with Competitors: Who Was Nearby

1. AMD Athlon II X2 270 (2011):

- Pros: cheaper, higher clock speed (3.4 GHz).

- Cons: no integrated graphics, higher TDP (65 W).

2. Intel Celeron G5905 (2020):

- Pros: supports DDR4, AVX2, Windows 11.

- Cons: new price — $50, single-core performance is 30% higher.

Practical Assembly Tips

1. SSD is Essential: even a Kingston A400 120 GB ($20) will speed up the system.

2. OS Optimization: use lightweight Linux distributions (Lubuntu, Xubuntu) or Windows 10 LTSC.

3. Cooling: the stock cooler is sufficient, but replace the thermal paste (e.g., Arctic MX-4).

4. Upgrade: if you need performance, look for processors at the level of Core i5-2500 ($10–20 used).

Final Conclusion: Who Should Consider the Pentium G840 in 2025

This processor is a choice for:

- Retro computing enthusiasts: building a nostalgic PC.

- Budget office systems: if tasks are limited to text and spreadsheets.

- Entry-level servers: for example, for data storage on Debian.

Why not to choose it:

- For $50–70, you can buy a new Celeron G6900 (2023), which is three times faster and supports DDR4.

- Even a used Core i5-3470 ($15) offers 4 cores and more capabilities.

Conclusion

The Intel Pentium G840 in 2025 is a relic that has a right to exist only in narrow scenarios. Its time has passed, but it can still be useful for minimalist tasks. However, in an era of DDR5 and 5-nm processors, investing in it makes sense only out of a love for experimentation or extreme budget constraints.

Basic

Label Name

Intel

Platform

Desktop

Launch Date

May 2011

Model Name

The Intel processor number is just one of several factors - along with processor brand, system configurations, and system-level benchmarks - to be considered when choosing the right processor for your computing needs.

G840

Code Name

Sandy Bridge

CPU Specifications

Total Cores

Cores is a hardware term that describes the number of independent central processing units in a single computing component (die or chip).

Total Threads

Where applicable, Intel® Hyper-Threading Technology is only available on Performance-cores.

Basic Frequency

2.80 GHz

Intel Hyper-Threading Technology

Intel® Hyper-Threading Technology (Intel® HT Technology) delivers two processing threads per physical core. Highly threaded applications can get more work done in parallel, completing tasks sooner.

Intel Turbo Boost Technology

Intel® Turbo Boost Technology dynamically increases the processor's frequency as needed by taking advantage of thermal and power headroom to give you a burst of speed when you need it, and increased energy efficiency when you don’t.

CPU Socket

The socket is the component that provides the mechanical and electrical connections between the processor and motherboard.

FCLGA1155

Technology

Lithography refers to the semiconductor technology used to manufacture an integrated circuit, and is reported in nanometer (nm), indicative of the size of features built on the semiconductor.

32 nm

TDP

65 W

PCI Express Version

PCI Express Revision is the supported version of the PCI Express standard. Peripheral Component Interconnect Express (or PCIe) is a high-speed serial computer expansion bus standard for attaching hardware devices to a computer. The different PCI Express versions support different data rates.

2.0

Instruction Set

The instruction set is a hard program stored inside the CPU that guides and optimizes CPU operations. With these instruction sets, the CPU can run more efficiently. There are many manufacturers that design CPUs, which results in different instruction sets, such as the 8086 instruction set for the Intel camp and the RISC instruction set for the ARM camp. x86, ARM v8, and MIPS are all codes for instruction sets. Instruction sets can be extended; for example, x86 added 64-bit support to create x86-64. Manufacturers developing CPUs that are compatible with a certain instruction set need authorization from the instruction set patent holder. A typical example is Intel authorizing AMD, enabling the latter to develop CPUs compatible with the x86 instruction set.

64-bit

Intel 64

Intel® 64 architecture delivers 64-bit computing on server, workstation, desktop and mobile platforms when combined with supporting software.¹ Intel 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory.

Yes

Memory Specifications

Memory Type

Intel® processors come in four different types: Single Channel, Dual Channel, Triple Channel, and Flex Mode. Maximum supported memory speed may be lower when populating multiple DIMMs per channel on products that support multiple memory channels.

DDR3 1066/1333

Max Memory Size

Max memory size refers to the maximum memory capacity supported by the processor.

32 GB

Memory Channels

The number of memory channels refers to the bandwidth operation for real world application.

Bus Speed

5 GT/s

Max Memory Bandwidth

Max Memory bandwidth is the maximum rate at which data can be read from or stored into a semiconductor memory by the processor (in GB/s).

21 GB/s

GPU Specifications

GPU Name

Intel® HD Graphics for 2nd Generation Intel® Processors

Graphics Base Frequency

Graphics Base frequency refers to the rated/guaranteed graphics render clock frequency in MHz.

850 MHz

Graphics Frequency

Graphics max dynamic frequency refers to the maximum opportunistic graphics render clock frequency (in MHz) that can be supported using Intel® HD Graphics with Dynamic Frequency feature.

1.10 GHz

Number of Displays Supported

Miscellaneous

Intel Virtualization Technology for Directed I/O (VT-d)

Intel® Virtualization Technology for Directed I/O (VT-d) continues from the existing support for IA-32 (VT-x) and Itanium® processor (VT-i) virtualization adding new support for I/O-device virtualization. Intel VT-d can help end users improve security and reliability of the systems and also improve performance of I/O devices in virtualized environments.

Intel Virtualization Technology (VT-x)

Intel® Virtualization Technology (VT-x) allows one hardware platform to function as multiple “virtual” platforms. It offers improved manageability by limiting downtime and maintaining productivity by isolating computing activities into separate partitions.

Yes

Instruction Set Extensions

Intel® SSE4.1 | Intel® SSE4.2

Enhanced Intel SpeedStep Technology

Enhanced Intel SpeedStep® Technology is an advanced means of enabling high performance while meeting the power-conservation needs of mobile systems. Conventional Intel SpeedStep® Technology switches both voltage and frequency in tandem between high and low levels in response to processor load. Enhanced Intel SpeedStep® Technology builds upon that architecture using design strategies such as Separation between Voltage and Frequency Changes, and Clock Partitioning and Recovery.

Yes

Execute Disable Bit

Execute Disable Bit is a hardware-based security feature that can reduce exposure to viruses and malicious-code attacks and prevent harmful software from executing and propagating on the server or network.

Yes

Cache

CPU Cache is an area of fast memory located on the processor. Intel® Smart Cache refers to the architecture that allows all cores to dynamically share access to the last level cache.

3 MB Intel® Smart Cache

Intel AES New Instructions

Intel® AES New Instructions (Intel® AES-NI) are a set of instructions that enable fast and secure data encryption and decryption. AES-NI are valuable for a wide range of cryptographic applications, for example: applications that perform bulk encryption/decryption, authentication, random number generation, and authenticated encryption.

Intel Clear Video HD Technology

Intel® Clear Video HD Technology, like its predecessor, Intel® Clear Video Technology, is a suite of image decode and processing technologies built into the integrated processor graphics that improve video playback, delivering cleaner, sharper images, more natural, accurate, and vivid colors, and a clear and stable video picture. Intel® Clear Video HD Technology adds video quality enhancements for richer color and more realistic skin tones.

Intel VT-x with Extended Page Tables (EPT)

Intel® VT-x with Extended Page Tables (EPT), also known as Second Level Address Translation (SLAT), provides acceleration for memory intensive virtualized applications. Extended Page Tables in Intel® Virtualization Technology platforms reduces the memory and power overhead costs and increases battery life through hardware optimization of page table management.

Yes

Intel InTru 3D Technology

Intel Flex Memory Access

Yes

Intel Quick Sync Video

Intel® Quick Sync Video delivers fast conversion of video for portable media players, online sharing, and video editing and authoring.

Benchmarks

Geekbench 6

Single Core Score

457

Geekbench 6

Multi Core Score

782

Geekbench 5

Single Core Score

518

Geekbench 5

Multi Core Score

942

Passmark CPU

Single Core Score

1267

Passmark CPU

Multi Core Score

1238

Compared to Other CPU

Geekbench 6 Single Core

FX-4170

530 +16%

Celeron 5305U

495 +8.3%

Pentium G840

457

Athlon II X2 280

423 -7.4%

Celeron G1610T

393 -14%

Geekbench 6 Multi Core

Celeron N4120

1022 +30.7%

A6-3650

927 +18.5%

Pentium G840

782

A8-3520M

667 -14.7%

A4 PRO-7300B

568 -27.4%

Geekbench 5 Single Core

Xeon E7-4870 v2

552 +6.6%

Xeon X5647

531 +2.5%

Pentium G840

518

Core i3-3120ME

504 -2.7%

Core i3-2120T

489 -5.6%

Geekbench 5 Multi Core

Core i5-2410M

1102 +17%

Pentium 4405U

1049 +11.4%

Pentium G840

942

A6-3500

863 -8.4%

Celeron G550T

795 -15.6%

Passmark CPU Single Core

Xeon E5-4607

1363 +7.6%

Xeon E5-4648 v3

1317 +3.9%

Pentium G840

1267

Athlon II X4 641

1207 -4.7%

Xeon E5640

1157 -8.7%

Passmark CPU Multi Core

Core i3-2100T

1488 +20.2%

Core i3-3217UE

1362 +10%

Pentium G840

1238

Celeron G550T

1102 -11%

Celeron 1017U

888 -28.3%