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Intel Pentium G645

Intel Pentium G645: A Detailed Review of an Outdated Processor for Budget Systems (2025)

Sandy Bridge Architecture and 32nm — Is It Worth Considering in 2025?

Key Specifications: A Legacy from 2011

The Intel Pentium G645 processor, released in 2012, is based on the Sandy Bridge microarchitecture. This generation was groundbreaking for its time, but by 2025, its capabilities appear archaic.

- Manufacturing Process: 32nm — In an era of 5nm chips like Apple's M3 and Intel's Meteor Lake, this metric indicates high power consumption and heat generation.

- Cores and Threads: 2 cores / 2 threads — insufficient for multitasking. For example, working simultaneously with a browser (10+ tabs) and office applications causes noticeable slowdowns.

- Clock Speed: 2.9 GHz (without Turbo Boost) — lower than modern budget Celeron processors (e.g., Celeron G6900: 3.4 GHz).

- Cache: 3 MB L3 — a minimum even for basic tasks.

- TDP: 65W — a modest figure, but efficiency lags behind modern counterparts.

- Performance: Geekbench 6 — 482 (Single-Core), 814 (Multi-Core). For comparison, the Intel Celeron G6900 (2023) scores around ~1500/2800.

Key Features: Support for SSE4.2 instructions and Intel Virtualization technology. In 2025, this is insufficient even for light task virtualization.

Compatible Motherboards: Searching for Rarities

The processor utilizes the LGA 1155 socket, which has not been supported since 2013.

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

- Issues in 2025:

- New motherboards are no longer manufactured. Prices for remaining stocks start from $80 (e.g., ASUS P8H61-M LX3 R2.0), which is expensive for an outdated platform.

- Limited functionality: USB 3.0 and SATA III are only available in high-end chipsets (Z68).

- No NVMe support without BIOS modification.

Tip: If building a system with the G645, look for used motherboards (price around $20–40), but be prepared for the risk of failure.

Supported Memory: Only DDR3

The processor works with DDR3-1066/1333 MHz memory.

- Limitations:

- Maximum capacity — 32 GB (theoretically), but most LGA 1155 motherboards support up to 16 GB.

- DDR3 bandwidth is 2–3 times lower than that of DDR4/DDR5. For instance, video rendering in HandBrake will take 30–40% longer compared to a system with DDR4-3200.

- Tip: Use dual-channel mode (2 modules of 4 GB) for a small performance boost.

Power Supply Recommendations

With a TDP of 65W, the Pentium G645 is not demanding on power supplies:

- System without discrete graphics: A 300W PSU is sufficient (e.g., be quiet! System Power 10 — $45).

- With graphics card: For GPU level NVIDIA GTX 1650 (TDP 75W), a 450W PSU will be required (EVGA 450 BR — $55).

Important: Older chipsets may not support modern energy-saving standards (such as C-states), increasing power consumption during idle periods.

Pros and Cons of the Pentium G645

Advantages:

- Price: New processors (if you can find them) cost $30–40.

- Compatibility with Windows 7/8: Ideal for specialized software requiring old operating systems.

- Low heat output: Suitable for compact cases (e.g., Dell OptiPlex 7010).

Disadvantages:

- Weak performance: Running Windows 11 is only possible through modifications, and performance in Photoshop or DaVinci Resolve is extremely slow.

- Outdated platform: No support for USB 3.1, Thunderbolt, Wi-Fi 6.

- Reliability risk: LGA 1155 components have been in use for over 10 years.

Use Cases: Only Basic Tasks

- Office Work: Word, Excel, email — acceptable but with an SSD.

- Multimedia: Watching 1080p video (YouTube, Netflix) — yes, but 4K is not supported.

- Gaming: Only older titles (Half-Life 2, CS:GO on low settings — 30–40 FPS).

Real Example: Pentium G645 + 8 GB DDR3 + 240 GB SSD + GT 1030 — a budget PC for studying ($150–200), but even Minecraft (version 1.20) only runs at 25–35 FPS.

Comparison with Competitors

- Intel Celeron G6900 (2023): 2 cores / 2 threads, but Alder Lake architecture (10nm), DDR4-3200, Geekbench 6 ~1500/2800. Price: $50–60.

- AMD Athlon 3000G (2019): 2 cores / 4 threads, Vega 3 GPU, support for DDR4-2666. Better performance in multitasking and gaming. Price: $60.

Conclusion: The Pentium G645 falls short against even budget CPUs from the 2020s, but may only be justified in extremely limited budget conditions.

Practical Assembly Tips

1. Choosing a Motherboard: Look for models with USB 3.0 (H67/Z68 chipsets).

2. Memory: 8–16 GB DDR3-1333 in dual-channel mode.

3. Storage: Definitely an SSD (Kingston A400 240 GB — $25).

4. Cooling: The stock cooler is sufficient, but replace it with an Arctic Alpine 12 ($15) for quieter operation.

5. Graphics Card: Avoid installing a GPU more powerful than the GTX 1050 Ti — the processor will become a bottleneck.

Final Verdict: Who Is the Pentium G645 Relevant for in 2025?

This processor should only be considered in extreme cases:

- Assembling the most inexpensive PC for text-based tasks (e.g., for a school office).

- Upgrading an old computer without replacing the motherboard.

- Creating specialized systems (e.g., data entry terminal).

Alternative: For $100–150, you can build a system based on a used Intel Core i5-3470 (4 cores / 4 threads) or AMD Ryzen 3 1200, which offer significantly better performance.

The Pentium G645 is a relic of the past that is justified in exceptional situations only in 2025. Its purchase makes sense only under strict budget constraints and without multitasking requirements.

Basic

Label Name

Intel

Platform

Desktop

Launch Date

July 2012

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.

G645

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

2.90 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

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).

17 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

482

Geekbench 6

Multi Core Score

814

Geekbench 5

Single Core Score

538

Geekbench 5

Multi Core Score

1016

Passmark CPU

Single Core Score

1321

Passmark CPU

Multi Core Score

1378

Compared to Other CPU

Geekbench 6 Single Core

Core i5-2405S

557 +15.6%

Celeron N4500

515 +6.8%

Pentium G645

482

Xeon E5-2650L

445 -7.7%

Xeon E5-4610 v4

412 -14.5%

Geekbench 6 Multi Core

Pentium Silver J5005

1031 +26.7%

Phenom II X4 850

934 +14.7%

Pentium G645

814

Pentium G620

675 -17.1%

Celeron 1037U

584 -28.3%

Geekbench 5 Single Core

Xeon E7-4830 v4

577 +7.2%

Pentium G2140

559 +3.9%

Pentium G645

538

Xeon E5-2658A v3

523 -2.8%

Xeon E5645

508 -5.6%

Geekbench 5 Multi Core

EPYC 7742

1163 +14.5%

Xeon E3-1505L v5

1082 +6.5%

Pentium G645

1016

Xeon E7-8860

910 -10.4%

A10-6790B

842 -17.1%

Passmark CPU Single Core

A6-5400B

1399 +5.9%

Core i7-3517U

1366 +3.4%

Pentium G645

1321

Xeon D-1520

1270 -3.9%

A8-3850

1217 -7.9%

Passmark CPU Multi Core

A6 PRO-7400B

1663 +20.7%

Pentium 4405Y

1526 +10.7%

Pentium G645

1378

Core i3-2350M

1252 -9.1%

Core i3-2312M

1120 -18.7%