We take a dekko at AMD's latest e series processors -

Don’t want your PC melting the ice caps while the electricity bill burns a hole in your pocket? Energy efficiency might well be the way to go and AMD has slotted in a couple of new additions to its processor line up that could help you out.

These chips are worth examining, and we're examining them in some detail. As usual, AMD pitches itself directly against Intel.

AMD is introducing the 415e and 610e, which have three and four cores respectively, while coming in with a TDP below 45w; making these some of the most energy-efficient mainstream chips on the market today.

We’re going to put these processors through their paces and see where they stand, both in terms of performance and power consumption.

AMD Athlon II X4 610e
Core Speed (MHz) 2400
Voltages 0.775-1.25
Max Temps (C) 72
Wattage 45 W
L1 X4 Cache Size (KB) 128
L2 X4 Cache Size (KB) 512
Socket AM3

AMD Athlon II X3 415e
Core Speed (MHz) 2500
Voltages 0.775-1.25
Max Temps (C) 72
Wattage 45 W
L1 X3 Cache Size (KB) 128
L2 X3 Cache Size (KB) 512
Socket AM3

These two sets of specs may look surprisingly similar to each other and there are very good reasons for that. The X3 415e is based on the Rana core, which is derived from the Propus core in the 610e with one of the cores disabled. Apparently, AMD targets defective cores to be disabled, however many new motherboards come with options to unlock the disabled core at the user’s own risk. The other big difference between these processors and their Phenom II counterparts is the absence of an L3 cache. With that in mind, we’re going to be looking at performance against some of AMD’s existing line up.

The test set-up contains an Asus CROSSHAIR IV FORMULA 890FX motherboard, 8Gb DDR3 1600mhz Kingston HyperX memory, a Western Digital VelociRaptor hard drive and a HIS AMD 5870 iCooler Turbo graphics card. The processors will be cooled by a Tuniq 120 extreme tower and we’re using Microsoft Windows 7. OK, so none of that is particularly energy efficient but it is necessary for comparison to existing offerings.

We’re putting these chips up against some of AMD’s existing energy-efficient range: the Phenom II X4 905e, the Athlon II X2 240e and for reference the Phenom II 1090T. The Asus Crosshair IV motherboard also comes with core unlocking capability, and with a simple press of 4 at start up, the 415e was running all four of its original cores. These processors aren’t aimed at the over-clocking market, but in the pursuit of thoroughness we’ve tried to get all we can out of each - with the 610e reaching 3GHz and the core unlocked 415e X4 reaching 3.2GHz whilst remaining stable.

For the benchmarks themselves, we’ll be looking at PCMark Vantage, 3DMark Vantage, x264 encoding, FPU Mandel benchmark and Dawn of War II.

Although a synthetic benchmark, PCMark Vantage does try and simulate real-world usage, running a suite of tests from image manipulation to web browsing. The program then scores each separately and combines to make one overall score; the higher the score the better. Looking at the results above, both new processors come out quite favourably against the competition, with the 415e X4 unlocked finishing above 610e and both challenging the 910e once over-clocked.

3Dmark Vantage is another synthetic test focusing on gaming and 3D performance. Testing both the GPU and CPU, we’re specifically looking at the CPU score, where higher is better. This test split the bunch more than the last, with the top-end Phenom II showing its caliber. The Unlocked 415e did well. Again, that “defective” core doesn’t look to be slowing it down much.

The H264 benchmark takes a 720p file and converts it to the x264 format. The conversion uses multiple passes and gives the average frame rate. The more frames per seconds it’s processing, the sooner the conversion will finish - so higher is better. The numbers are pretty much as expected, although the 610e was more deserving of its price tag this time round, getting near the performance of the Phenom II 910e.

Everest Ultimate contains a number of interesting benchmarks, including one called Mandel, which measures 64-Bit Floating point calculations and is based on the “Mandlebrot” fractal; the higher the score the better. This is another area where the unlocked 415e did very well, ending up closer to its Phenom II 905e than the 610e.

Last on the list of benchmarks is Dawn of War II. This RTS game can provide a bit of a challenge for CPU/GPU combinations. It doesn’t look to be particularly multithreaded, though, as all the Athlon II are quite equal no matter how many cores, with the dual core 240e doing particularly well.

We also ran the Alien Vs Predator DirectX 11 benchmark but this seems to only really test the graphics card, with all the CPU scoring in the 60-65FPS range.

Although they have shown to be no slouch when it comes to performance the main selling point of these CPUs is the 45w TDP; as such, we also had a look at the power usage, while both idle and under load. We took the load readings while running the Everest Ultimate Mandel benchmark, as this had all cores at 100%.

The results of the power comparison came back pretty much as expected, with the 610e drawing a little more power than the 415e until you start over-clocking, in which case it was reasonably even. Both chips were consistently using less power than the 905e.

We didn’t feel that our test set-up really represented actual usage, so to see how low we could see power consumption we exchanged the 5870 graphics card for a 5450, which uses around 20w under load, and removed a couple of sticks of the ram to leave 4Gb. We then re-ran the same test without any overclocking or tweaking.

The power consumption with the modifications to the test rig was nothing short of fantastic, with the 415e drawing slightly under 100W, even while under load. The 610e was only slightly higher than that, coming just above the 100W mark. Looking at the performance these processors have delivered, and the extremely efficient way they are doing it, we find it difficult to see a downside to them. AMD has a really great line-up in this part of the market and the 415e and 610e slot in perfectly.

The 415e was of particular interest given its sub £100 price tag, particularly if you have a motherboard that can reactivate that fourth core for you, although some of those cores would have to be deactivated for good reasons, so you might have very different results to us.

If you’re considering buying an energy-efficient processor but don’t want to compromise on performance, AMD’s latest three- and four-core offerings, the 415e and 610e, don’t disappoint. Given their price and low power credentials, we don’t hesitate to recommend.

Product: AMD Athlon II X4 610e

Website: http://www.amd.com/

Street Price: £120


Product: AMD Athlon II X3 415e

Website: http://www.amd.com/

Street Price: £85