Skip to navigation

AMD Athlon II X4 635 review

AMD Athlon II X4 635


Performs a little too slowly and costs too much; overshadowed by better value rivals

Review Date: 19 Feb 2010

Reviewed By: Darien Graham-Smith

Price when reviewed: £82 (£96 inc VAT)

Overall Rating
3 stars out of 6

Features & Design
3 stars out of 6

Value for Money
3 stars out of 6

4 stars out of 6

AMD keeps turning out CPUs with different configurations of clock speeds, cores and cache, to the point where it seems that soon every possible combination will be on the market. Not every combination can be a winner, however.

This latest Athlon II is a case in point: it’s generously endowed with four physical cores, but then hobbled by the absence of an L3 cache. The net result is, predictably, mediocre performance: running at a stock speed of 2.9GHz on a Vista system with 2GB of RAM, the X4 635 delivered an overall benchmark score of just 1.55. That’s fine for everyday applications – we regularly recommend laptops with half the performance. But compared with most of Intel’s Core i3 range it’s off the bottom of the chart.

In fairness, the Athlon II X4 635 is at least within sight of the low-end Core i3-530, which scored 1.58 overall. It even beat that chip in our 2D graphics test, scoring 1.92 against the Core i3’s 1.72. It narrowly won in the multitasking test too, scoring 1.75 versus 1.74. But, since the Athlon has four real cores, while the i3 relies on doubling up its twin cores with Hyper-Threading, the thinness of the Athlon’s victory is telling.

In our other tests the Athlon was a clear loser, managing only 1.13 and 1.40 in our Office and encoding exercises, while the i3 scored 1.29 and 1.56 respectively. Since the two chips are almost identically clocked (the Core i3-530 runs at 2.93GHz), you have to conclude that Intel’s baby is simply better engineered.

Predictably, the Core i3’s 32nm architecture brings lower power demands too, idling at just 31W on our LGA 1156 test system and peaking at 79W. Our Athlon system, running on a motherboard with integrated ATI Radeon 4290 graphics, idled at 55W, rising to 113W when we pushed it hard.

If AMD’s chips don’t match the technical sophistication of their rivals, the company generally makes it up with aggressive pricing, but right now you’ll pay more for an X4 635 than for an i3-530, and it’s not even competitive with AMD’s own Phenom II X2 555. Sure, that model has only two cores, but with a healthy 6MB L3 cache and a faster clock speed it’s still faster in our benchmarks, and £16 cheaper.

All told, the Athlon II X4 635 is a chip with little going for it. Don’t be tempted by its four cores: you’ll get more performance for your money elsewhere.

Author: Darien Graham-Smith

Subscribe to PC Pro magazine. We'll give you 3 issues for £1 plus a free gift - click here
User comments

"But compared with most of Intel’s Core i3 range it’s off the bottom of the chart".

Does Intel have a Most Of Core i3 Chart?

- Thought Not!

"Intel’s baby is simply better engineered". You are compairing different generations of technologies, what do you expect to find?

Which is the more powerful for crunching?

By skgiven on 4 Mar 2010


Be careful of the numbers here. Compare the numbers this review with the numbers here:

which extol the virtues of the Phenom vs i3.

The specific numbers for specific tests don't agree. In fact, the reason I chose the then available Athlon IIx4 630 was the particularly good numbers in 2D. But what also has to be taken in serious consideration is the video card's 2D performance.

By LawrenceHudetz on 4 Mar 2010

Just to be clear, the Phenom II X2 255 is good value compared to the similarly-performing Core i3-540, while this model, the Athlon II X4 635, is worse value than the better-performing Core i3-530.

By DarienGS on 5 Mar 2010

Leave a comment

You need to Login or Register to comment.


Latest Category Reviews
Intel Devil's Canyon review

Intel Devil's Canyon

Category: Processors
Rating: 5 out of 6
Price: £263
AMD Kaveri review

AMD Kaveri

Category: Processors
Rating: 4 out of 6
Price: £0
AMD Richland review

AMD Richland

Category: Processors
Rating: 5 out of 6
Price: £115
Intel Haswell review

Intel Haswell

Rating: 5 out of 6
Price: £115
AMD Trinity review

AMD Trinity

Category: Processors
Rating: 5 out of 6
Price: £91
Compare reviews: Processors


Most Commented Reviews
Latest News Stories Subscribe to our RSS Feeds
Latest Blog Posts Subscribe to our RSS Feeds
Latest Features
Latest Real World Computing


Sponsored Links


Your email:

Your password:

remember me


Hitwise Top 10 Website 2010

PCPro-Computing in the Real World Printed from

Register to receive our regular email newsletter at

The newsletter contains links to our latest PC news, product reviews, features and how-to guides, plus special offers and competitions.