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AMD Phenom II X4 940 Black Edition review




  • Recommended by TR
AMD Phenom II X4 940 Black Edition


Our Score:


Today AMD released the latest addition to its CPU line-up, the aptly named Phenom II range. These quad core processors will eventually completely replace the existing Phenom series and, for the foreseeable future, be AMD's answer to Intel's new Core i7 processors.

For today's launch there will be only two processors available, the Phenom II 940 Black Edition and Phenom II 920. The former will run at 3.0GHz (a marked increase from the previous Phenom's best of 2.6GHz) and cost a relatively modest $275 while the latter runs at 2.8GHz and comes at an even more reasonable $235. Compare this to the prices of even the cheapest Core i7 and it doesn't take a genius to work out that these Phenoms, despite their improvements, won't be gunning for the top performance spot. Nonetheless, considering how little most of us utilise the power of even modest dual-core processors, there's still plenty of reason to consider AMD's latest.

The key difference between the first generation Phenoms and the Phenom IIs is the move from manufacturing the chips on a 65nm process to a 45nm process. This yields chips that consume less power and produce less heat than the equivalent designs on the older process, which means CPUs can either run at the same speed as before but consume less power or run faster for the same power usage.

Another result of the shrink is either an increase in the number of chips that can be produced per wafer of silicon (making them cheaper) or that the same number of chips can be produced with more logic crammed into the same space.

It's this latter route that AMD has taken with the Phenom II. The actual chip is almost identical in size to the existing Phenom but it incorporates around two thirds more transistors - up from ~450 million to ~758 million.

A large proportion of this extra silicon is taken up by an increased amount of on-die cache memory. Just like previous Phenoms, Phenom II uses three levels of cache with the first two levels remaining at 128KB (64KB for instructions, 64KB for data) and 512KB per core. However, the third L3 level has increased from 2MB all the way up to 6MB, which is shared by all four cores. AMD estimates this accounts for around a five per cent performance increase over previous Phenoms. Obviously this is something that's impossible for us to test directly so we'll have to take its word for it.

Besides the cache and clock frequency increases, there aren't too many fundamental changes to the core CPU design. That said, a number of tweaks have been made to both increase performance and reduce power usage.

For a start, AMD has improved Cool and Quiet (CnQ) - the technology that reduces clock speeds when parts of the processor are idle. The previous incarnation would dynamically clock each core independently, which in theory sounds great but because of the way Windows Vista handles the distribution of tasks across multi-core processors, it could result in reduced performance. But by going backwards and simplifying the CnQ to dynamically clock all four cores at once, the new Phenoms don't see a performance hit anymore. So it's now safe to have CnQ on all the time.


January 8, 2009, 11:57 pm

In the system specs you state that the

i7 was 2/3 x 1gb DDR3

Core2 was 2 x 1gb DDR3

Phenom 2 was 1 x 1gb DDR2

Is this correct that the Phenom only had 1gb ram? As surely that would affect benchmarks.


January 9, 2009, 12:07 am

Nope, incorrect. Corrected now.


January 9, 2009, 11:43 am

how would this have compared to common dual core setups and an intel q6600 (overclocked)?


January 9, 2009, 2:54 pm

How much difference do we think DDR3 memory makes, in these speed tests?

The MP3 test is very interesting. By the way, how many simultaneous MP3 encodes were happening on the Intel quad-cores with hyperthreading - was it 8? And does this test not suggest that Intel processors are way more efficient at thread synchronising, but when a Phenom II is allowed to chug through a task on each physical core without much thread synchronisation then the AMD is actually about as fast?

(Thread synchronisation is the guilty secret of multicore computing. It stops multi-threaded tasks being as fast as they could in theory be. In simple terms, where two threads need to access the same data - which is surprisingly often in programs where multiple threads have to co-operate on the same task - then the L1 and L2 cache of all cores needs to be flushed to actual RAM, before any thread can be sure that the data will be read correctly. Flushing the cache is a time-consuming operation. Maybe Intel have a way to do this more efficiently? Maybe it is just because of Intel's new memory controller and DD3?)


January 11, 2009, 5:02 am

I agree it would be advantageous to see this processor compared with the Q6600. The decision is either plop a 6600 into the motherboard, Jump to core i7 or switch to AMD. The Q6600 sems still to be holding its own and is of a similar pricepoint


February 2, 2009, 2:05 pm

edward you might want to trow in a Q9400/Q9300 as a direct comparison based on price

as all the intels cpus in this review is all above $300, the i7 920 platform cost twice that of a a AMD Phenom 940 platform, and the QX9770 costs over $1000+, even the i7 965 cost $1000+, whine the nice Phenom II 940 is $230


March 12, 2009, 5:29 pm

i know this is off topic but "empire total war" is still slow on this cpu even when overclocked to 3.2ghz. the load time is killing it.


April 25, 2009, 5:10 am

Ya know from reading this thread; my conclusion is this.

This is no different than the arguement over Chevy vs. Ford and who is better.

All I have seen is nothing but a FPS war of numbers.

Yes Intel crunches number faster in some cases; but look at the price you pay...


I just assembled a Phenom 940 3.0 ghz, EVGA 730a, 4 gig DDR2 800, ATI 4870 PCI-E card. Liquid cooling from Domino ALC.

I have yes pushed it stale at stock Vcore to 3.6 ghz.

I play Bioshock and Crysis at 1600x1200 max monitor will go to. I can whip things around while playing and no studdering or pausing and MOST OF ALL NO CRASHING. I run at 37-40 temp all the time.

I spent $900.00 assembling this system. For just a Intel i7 Quad Core CPU costs almost $1,000.00; then add everything else.

The system does what I want it too and It does the job also.

Have fun...:-P

mechanical software

August 28, 2013, 6:29 pm

Cinebench has both a single-threaded and multi-threaded test while POV-Ray is just multi-threaded.

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