Buldozer Vs i3

Now, we used a very high-end Radeon HD 7970 graphics card in that article because we wanted to isolate CPU performance. You can't draw conclusions about a CPU's potential when you're faced with a graphics card bottleneck, after all. But some of our readers rightly pointed out that, when it comes to building an inexpensive machine, our combination is unrealistic. A $110 CPU would never accompany a $550 graphics card. And if we used an entry-level GPU, the resulting bottleneck would have masked the differences between processors to a greater extent. The counter, of course, is that a cheaper graphics card would have also imposed lower resolutions and detail settings, shifting load back in the direction of the CPU.
As you know, though, we put a big emphasis on addressing your feedback, so we went back to the lab to run some follow-up data on two of the most interesting $120 options from our previous story. Intel's Core i3-2100 is the low-cost processor to beat, so we made sure to include it. On the other hand, with AMD's Phenom II and Athlon II lines disappearing from store shelves, the $110 FX-4100 represents that company’s best low-priced option.

APU VS SANDY BRIDGE

Up until now, we've primarily gauged performance based on stock clock rates. However, most of Intel's CPU suffer manufacturer-imposed limitations on overclocking, while AMD facilitates a more enthusiast-friendly attitude to the modification of its chips.
Given this significant differentiation, we thought it important to more aggressively tune the multiplier-unlocked models in our round-up to see how the results change.
Because StarCraft II proved to be such a good indicator of processor performance, we'll start our testing with that game.


All of the overclocked models (except AMD's A8-3870K) post notable performance gains, with results comparable to Intel's stock Core i3-2100. With that in mind, though, none of the processors come close to challenging an unmodified Core i5-2400.


Overclocking helps each of AMD's unlocked chips gain in meaningful ways. However, none can reach the Core i3-2100's minimum frame rate. Meanwhile, the Core i5-2400 remains comfortably out of reach.


A trend emerges in this third data point. The overclocked processors perform behind or close to a stock Core i3-2100.

APU A3850 Overclock

AMD Fusion APU Overclocking

When AMD released the 'Lynx' desktop platform back in June 2011, our motherboard reviewer ran into some bad luck when overclocking the processor. When you get a new platform setup for the very first time you really don't know what to expect and it does take some time to learn all the quirks and nuances of a new processor and motherboard. When our motherboard reviewer, Dan Stoltz, reviewed the ASUS F1A75-M motherboard and the MSI A75MA-G55 motherboard we found that the AMD A8-3850 that we had wasn't a good overclocker. Some people think that AMD likes to send out cherry picked processors, but trust us that isn't the case.




Since we want to see how well AMD A75 chipset powered motherboard overclock we got our hands on six additional AMD A8-3850 tray processors and now had a total of seven of them in our possession. Our point of doing this was to get the best one for our test system. After testing each processor we thought we'd share the results with you as this is a great example of what you can expect when you buy a processor.







The A8-3850 has a 2.9GHz quad-core CPU, 600MHz GPU w/ 400 Radeon cores, 4MB of L2 cache and a 100W TDP. The processor has a base clock of 100MHz with a multiplier of 29. This is a locked multiplier, so you can lower the multiplier in the BIOS, but you can not increase it. That means for overclocking we are limited to just increasing the base clock frequency in the motherboards BIOS.




For testing we used the ASRock A75 Pro4 motherboard with a Ultra Carbon X5 CPU cooler and set the vCore at 1.500V and started cranking up the baseclock or bus speed on the seven processors that we had. Stock voltage on this board was 1.325V. We didn't go crazy with the voltage, but we did find some differences between the seven processors that we had in our possession with this voltage bump.





AMD A8-3850 APU

Max Baseclock

Max Frequency


CPU #1

114MHz

3303.1 MHz


CPU #2

127MHz

3679.5 MHz


CPU #3

127MHz

3679.5 MHz


CPU #4

127MHz

3679.5 MHz


CPU #5

127MHz

3679.5 MHz


CPU #6

127MHz

3679.5 MHz


CPU #7

132MHz

3826.5 MHz
The original test sample that AMD sent us actually turned out being the least overclockable APU and was able to hit just 114 MHz on the baseclock for final clock frequency of 3.30 GHz. The best overclocker in the group of seven was an APU that could run stable at 132 MHz or 3.83 GHz.






As you can see the difference between the best and worst processor was 523.4 MHz, which is very significant. The other five AMD A8-3850 APU's all topped our at 127MHz or 3.70GHz. It was a little shocking to see the vast majority of the processors hitting the same speed, but to see six out of the seven APUs reaching 800MHz overclocks was very nice.




Just to show you the advantages of overclocking here is a 3DMark Vantage run showing the score a stock AMD A8-3850 APU being P4166 and then our best overclocker running 3.83GHz having a score of P5059! We were able to break the 5,000 mark by the overclock. Getting a 21% boost in the benchmarks is a nice performance gain!




At the end of the day we found that once again not all processors overclock to the same level and that our original AMD A8-3850 APU was a poor overclocker. We'll be updating our motherboard test system to the best overclocking processor as we want to make sure we aren't processor limited as we want to show you the differences between different brands and not be held back by a Fusion APU that wasn't overclocking to a level that we expected.

Usually we don't show what goes on behind the scenes of Legit Reviews, but we thought you'd get a kick out of it. If you'd like to see more short articles like this in the future be sure to let us know!