Phenom X4 9850B vs Xeon E5603

Phenom X4 9850B vs Xeon E5603 Performance Spectrum

Phenom X4 9850B

4 / 4

1,946

+0.6%

Ryzen Threadripper PRO 7955WX

Ryzen Threadripper 3990X

Xeon E5603

4 / 4

1,935

0.0%

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.

Phenom X4 9850B vs Xeon E5603 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.

Phenom X4 9850B vs Xeon E5603: Pros, Cons & Final Verdict

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

Phenom X4 9850B

2008

Why buy it

Trade-offs

❌Smaller total L3 cache (2 MB vs 4 MB).
❌Less compelling for workstation-style loads than Xeon E5603, which brings 4 cores / 4 threads and 32 PCIe lanes.
❌18.8% higher power demand at 95W vs 80W.

Xeon E5603

2011

Why buy it

✅+100% larger total L3 cache (4 MB vs 2 MB).
✅Better for workstations and heavier parallel workloads: 4 cores / 4 threads, plus 32 PCIe lanes vs 0.
✅Draws 80W instead of 95W, a 15W reduction.
✅100+% more PCIe lanes (32 vs 0) for storage and expansion-heavy builds.

Trade-offs

❌Lower PassMark (1,935 vs 1,946).
❌Launch MSRP is still $188 MSRP, while Phenom X4 9850B mostly shows up through inconsistent older-market listings.

Quick Answers

So, is Phenom X4 9850B better than Xeon E5603?

Not really, because they are built for different jobs. Xeon E5603 makes more sense for workstation-style multi-core throughput, while Phenom X4 9850B is the more practical desktop choice for gaming, platform cost, and everyday use.

Which one is better for gaming?

If gaming is the priority, Phenom X4 9850B is the better pick. According to our tests, it delivers 2.2% more average FPS across 50 shared CPU game tests.

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

For streaming, content creation, and heavier multitasking, Phenom X4 9850B is the stronger fit. You are getting 0.6% better PassMark, backed by 4 cores and 4 threads.

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

Phenom X4 9850B is still the faster CPU overall, but Xeon E5603 is easier to justify if budget matters more than peak performance. Phenom X4 9850B comes in at an unclear MSRP at unclear MSRP versus $188 MSRP, and it still gives you a 2.2% average FPS lead across 50 shared CPU game tests in our data. Xeon E5603 is also 100.0% better value on MSRP (10.3 vs 0.0 PassMark/$), which is why it can still make sense for tighter-budget builds on paper.

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

Xeon E5603 makes more sense long term for 2026 and beyond. You are getting a newer CPU generation (2011 vs 2008) and 100% larger total L3 cache (4 MB vs 2 MB). That makes it the safer long-term bet.

Phenom X4 9850B vs Xeon E5603 Technical Specifications

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

Phenom X4 9850B

The Phenom X4 9850B is manufactured by AMD. It was released in 2009-01-01. It is based on the Agena (2007−2008) architecture. It features 4 cores and 4 threads. Max frequency: 2.5 GHz. L3 cache: 2 MB (total). L2 cache: 512 kB (per core). Built on 65 nm process technology. Socket: AM2+. Thermal design power (TDP): 95 Watt. Passmark benchmark score: 1,946 points. Launch price was $149.

Xeon E5603

The Xeon E5603 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 4 cores and 4 threads. Base frequency is 1.6 GHz, with boost up to 1.6 GHz. L3 cache: 4 MB (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: 1,935 points. Launch price was $286.

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Processing Power

Both the Phenom X4 9850B and Xeon E5603 share an identical 4-core/4-thread configuration. Boost clocks reach 2.5 GHz on the Phenom X4 9850B versus 1.6 GHz on the Xeon E5603 — a 43.9% clock advantage for the Phenom X4 9850B. The Phenom X4 9850B uses the Agena (2007−2008) architecture (65 nm), while the Xeon E5603 uses Westmere-EP (2010−2011) (32 nm). In PassMark, the Phenom X4 9850B scores 1,946 against the Xeon E5603's 1,935 — a 0.6% lead for the Phenom X4 9850B. L3 cache: 2 MB (total) on the Phenom X4 9850B vs 4 MB (total) on the Xeon E5603.

Feature	Phenom X4 9850B	Xeon E5603
Cores / Threads	4 / 4	4 / 4
Boost Clock	2.5 GHz+56%	1.6 GHz
Base Clock	—	1.6 GHz
L3 Cache	2 MB (total)	4 MB (total)+100%
L2 Cache	512 kB (per core)+100%	256 kB (per core)
Process	65 nm	32 nm-51%
Architecture	Agena (2007−2008)	Westmere-EP (2010−2011)
PassMark	1,946	1,935

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Memory & Platform

The Phenom X4 9850B uses the AM2+ socket (PCIe 2.0), while the Xeon E5603 uses LGA1366 (PCIe 2.0) — making them incompatible on the same motherboard.