Xeon D-1521 vs Xeon E5649

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.

Xeon D-1521 vs Xeon E5649 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.

Xeon D-1521 vs Xeon E5649: Pros, Cons & Final Verdict

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

Xeon D-1521

2015

Why buy it

✅+0.8% higher PassMark.
✅Costs $575 less on MSRP ($199 MSRP vs $774 MSRP).
✅Delivers 292.0% more PassMark for each dollar spent, at 28.7 vs 7.3 PassMark/$ ($199 MSRP vs $774 MSRP).
✅Draws 45W instead of 80W, a 35W reduction.

Trade-offs

❌Smaller total L3 cache (1.5 MB vs 12 MB).

Xeon E5649

2011

Why buy it

✅+700% larger total L3 cache (12 MB vs 1.5 MB).

Trade-offs

❌Lower PassMark (5,659 vs 5,703).
❌Lower PassMark per dollar, at 7.3 vs 28.7 PassMark/$ ($774 MSRP vs $199 MSRP).
❌77.8% higher power demand at 80W vs 45W.

Quick Answers

So, is Xeon D-1521 better than Xeon E5649?

It depends on what you want from the system. For gaming, Xeon E5649 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, Xeon D-1521 pulls ahead with 0.8% better PassMark. Xeon E5649 also has the bigger cache pool with 700% larger total L3 cache (12 MB vs 1.5 MB).

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

For streaming, content creation, and heavier multitasking, Xeon D-1521 is the stronger fit. You are getting 0.8% better PassMark, backed by 4 cores and 8 threads.

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

Xeon D-1521 is the better buy right now. Xeon D-1521 comes in $575 cheaper on MSRP at $199 MSRP versus $774 MSRP, and it still gives you 0.8% better PassMark. The compromise is that Xeon E5649 is still the better pure gaming CPU with a 0.4% average FPS lead across 50 shared CPU game tests in our data. It is also 292.0% better value on MSRP (28.7 vs 7.3 PassMark/$), so you are getting the faster CPU without taking a value hit on paper.

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

Xeon D-1521 makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2015 vs 2011) and more multi-core headroom with 4 cores / 8 threads instead of 6/12. That extra compute headroom is more likely to matter as games, background tasks, and creator workloads get heavier.

Xeon D-1521 vs Xeon E5649 Technical Specifications

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

Xeon D-1521

The Xeon D-1521 is manufactured by Intel. It was released in 1 November 2015 (10 years ago). It is based on the Broadwell (2015−2019) architecture. It features 4 cores and 8 threads. Base frequency is 2.4 GHz, with boost up to 2.7 GHz. L3 cache: 1.5 MB (per core). L2 cache: 256K (per core). Built on 14 nm process technology. Socket: FCBGA1667. Thermal design power (TDP): 45 Watt. Memory support: DDR4, DDR3. Passmark benchmark score: 5,703 points. Launch price was $199.

Xeon E5649

The Xeon E5649 is manufactured by Intel. It was released in 14 February 2011 (14 years ago). It is based on the Westmere-EP (2010−2011) architecture. It features 6 cores and 12 threads. Base frequency is 2.53 GHz, with boost up to 2.93 GHz. L3 cache: 12288 kB (total). L2 cache: 256 kB (per core). Built on 32 nm process technology. Socket: LGA1366. Thermal design power (TDP): 80 Watt. Memory support: DDR3. Passmark benchmark score: 5,659 points. Launch price was $45.

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Processing Power

The Xeon D-1521 packs 4 cores / 8 threads, while the Xeon E5649 offers 6 cores / 12 threads — the Xeon E5649 has 2 more cores. Boost clocks reach 2.7 GHz on the Xeon D-1521 versus 2.93 GHz on the Xeon E5649 — a 8.2% clock advantage for the Xeon E5649 (base: 2.4 GHz vs 2.53 GHz). The Xeon D-1521 uses the Broadwell (2015−2019) architecture (14 nm), while the Xeon E5649 uses Westmere-EP (2010−2011) (32 nm). In PassMark, the Xeon D-1521 scores 5,703 against the Xeon E5649's 5,659 — a 0.8% lead for the Xeon D-1521. L3 cache: 1.5 MB (per core) on the Xeon D-1521 vs 12288 kB (total) on the Xeon E5649.

Feature	Xeon D-1521	Xeon E5649
Cores / Threads	4 / 8	6 / 12+50%
Boost Clock	2.7 GHz	2.93 GHz+9%
Base Clock	2.4 GHz	2.53 GHz+5%
L3 Cache	1.5 MB (per core)	12288 kB (total)+700%
L2 Cache	256K (per core)	256 kB (per core)
Process	14 nm-56%	32 nm
Architecture	Broadwell (2015−2019)	Westmere-EP (2010−2011)
PassMark	5,703	5,659
Geekbench 6 Single	—	415
Geekbench 6 Multi	—	2,109

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Memory & Platform

The Xeon D-1521 uses the FCBGA1667 socket (PCIe 3.0), while the Xeon E5649 uses LGA1366 (PCIe 5.0) — making them incompatible on the same motherboard.

Feature	Xeon D-1521	Xeon E5649
Socket	FCBGA1667	LGA1366
PCIe Generation	PCIe 3.0	PCIe 5.0+67%
Max RAM Speed	—	DDR3 1333 MHz
Max RAM Capacity	—	288 GB
RAM Channels	—	3
ECC Support	—	Yes
PCIe Lanes	—	0

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Advanced Features

Virtualization: not specified (Xeon D-1521) / true (Xeon E5649). Primary use case: Xeon E5649 targets Server.

Feature	Xeon D-1521	Xeon E5649
Integrated GPU	—	No
Unlocked	—	No
AVX-512	—	No
Virtualization	—	true
Target Use	—	Server

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Value Analysis

At launch, the Xeon D-1521 was priced at $199, while the Xeon E5649 came in at $774. On launch pricing ($199 vs $774), Xeon D-1521 was $575 cheaper. In terms of value on MSRP (PassMark points per dollar), the Xeon D-1521 delivers 28.7 pts/$ vs 7.3 pts/$ for the Xeon E5649 — making the Xeon D-1521 the 118.7% better value option.

Feature	Xeon D-1521	Xeon E5649
MSRP	$199-74%	$774
Performance per Dollar	28.7+293%	7.3
Release Date	2015	2011

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