Core 2 Duo T6400 vs Phenom II X4 820

Core 2 Duo T6400 vs Phenom II X4 820 Performance Spectrum

Core 2 Duo T6400

2 / 2

2,115

0.0%

2,114

0.0%

Ryzen Threadripper PRO 7955WX

Ryzen Threadripper 3990X

About PassMark

PassMark CPU Mark evaluates processor speed through complex mathematical computations. It provides a reliable metric to compare multi-core performance, where higher scores indicate faster processing for multitasking, gaming, and heavy workloads.

Core 2 Duo T6400 vs Phenom II X4 820 FPS Benchmarks

Predicted gaming performance across popular games. Tested paired with GeForce RTX 5090 to isolate CPU performance.

Search any supported game below to compare 1080p FPS for both components.

Core 2 Duo T6400 vs Phenom II X4 820: Pros, Cons & Final Verdict

See where each CPU makes more sense in practice: gaming, heavier work, platform cost, power draw, and upgrade path.

Core 2 Duo T6400

2009

Why buy it

✅+0% higher PassMark.
✅Draws 2W instead of 95W, a 93W reduction.

Trade-offs

❌Smaller total L3 cache (2 MB vs 4 MB).

Phenom II X4 820

2009

Why buy it

✅+100% larger total L3 cache (4 MB vs 2 MB).

Trade-offs

❌Lower PassMark (2,114 vs 2,115).
❌Launch MSRP is still $150 MSRP, while Core 2 Duo T6400 mostly shows up through inconsistent older-market listings.
❌4650% higher power demand at 95W vs 2W.

Quick Answers

So, is Core 2 Duo T6400 better than Phenom II X4 820?

It depends on what you want from the system. For gaming, Phenom II X4 820 is ahead with a 0.4% average FPS lead across 50 shared CPU game tests in our data. For rendering, compiling, streaming, and heavier multitasking, Core 2 Duo T6400 pulls ahead with 0% better PassMark. Phenom II X4 820 also has the bigger cache pool with 100% larger total L3 cache (4 MB vs 2 MB).

Which one is better for streaming, content creation, and heavy multitasking?

For streaming, content creation, and heavier multitasking, Core 2 Duo T6400 is the stronger fit. You are getting 0% better PassMark, backed by 2 cores and 2 threads.

Which one is the smarter buy today, not just the cheaper CPU?

Core 2 Duo T6400 is still the much better call for a fresh build. Core 2 Duo T6400 comes in at an unclear MSRP at unclear MSRP versus $150 MSRP, and it still gives you 0% better PassMark. Phenom II X4 820 only looks stronger on raw value math because it is extremely cheap, but that usually means used-market pricing on an obsolete 2009 platform. Even with 100.0% better value on paper (14.1 vs 0.0 PassMark/$), it really only makes sense as a cheap stopgap or a niche existing-platform option for someone already on AM3.

Which one is more future-proof for 2026 and beyond?

Phenom II X4 820 is the safer long-term CPU choice because it gives you more room to grow and a better platform outlook.

Core 2 Duo T6400 vs Phenom II X4 820 Technical Specifications

Side-by-side specs, architecture details, clocks, memory, power, and platform differences.

Core 2 Duo T6400

The Core 2 Duo T6400 is manufactured by Intel. It was released in 2008-01-01. It is based on the Penryn (2008−2011) architecture. It features 2 cores and 2 threads. Base frequency is 2 GHz, with boost up to 2 GHz. L3 cache: 2 MB L2 Cache. L2 cache: 2 MB. Built on 45 nm process technology. Socket: PGA478. Thermal design power (TDP): 35 Watt. Passmark benchmark score: 2,115 points. Launch price was $249.

Phenom II X4 820

The Phenom II X4 820 is manufactured by AMD. It was released in 1 September 2009 (16 years ago). It is based on the Deneb (2009−2011) architecture. It features 4 cores and 4 threads. Base frequency is 2.8 GHz, with boost up to 2.8 GHz. L3 cache: 4 MB (total). L2 cache: 512 kB (per core). Built on 45 nm process technology. Socket: AM3. Thermal design power (TDP): 95 Watt. Memory support: DDR3. Passmark benchmark score: 2,114 points. Launch price was $90.

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Processing Power

The Core 2 Duo T6400 packs 2 cores / 2 threads, while the Phenom II X4 820 offers 4 cores / 4 threads — the Phenom II X4 820 has 2 more cores. Boost clocks reach 2 GHz on the Core 2 Duo T6400 versus 2.8 GHz on the Phenom II X4 820 — a 33.3% clock advantage for the Phenom II X4 820 (base: 2 GHz vs 2.8 GHz). The Core 2 Duo T6400 uses the Penryn (2008−2011) architecture (45 nm), while the Phenom II X4 820 uses Deneb (2009−2011) (45 nm). In PassMark, the Core 2 Duo T6400 scores 2,115 against the Phenom II X4 820's 2,114 — a 0% lead for the Core 2 Duo T6400. L3 cache: 2 MB L2 Cache on the Core 2 Duo T6400 vs 4 MB (total) on the Phenom II X4 820.

Feature	Core 2 Duo T6400	Phenom II X4 820
Cores / Threads	2 / 2	4 / 4+100%
Boost Clock	2 GHz	2.8 GHz+40%
Base Clock	2 GHz	2.8 GHz+40%
L3 Cache	2 MB L2 Cache	4 MB (total)+100%
L2 Cache	2 MB+300%	512 kB (per core)
Process	45 nm	45 nm
Architecture	Penryn (2008−2011)	Deneb (2009−2011)
PassMark	2,115	2,114
Geekbench 6 Single	650	—
Geekbench 6 Multi	1,300	—

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Memory & Platform

The Core 2 Duo T6400 uses the PGA478 socket (PCIe 1.1), while the Phenom II X4 820 uses AM3 (PCIe 2.0) — making them incompatible on the same motherboard.