AMD's APU Appeals To Value, But LGA 1155 Scales Effortlessly
Before we break into analysis, let’s look at the aggregate results. These numbers represent the total average performance of each solution relative the top result in each test:
We can hardly be surprised by the outcome. Intel's Pentium G620 and AMD's Radeon HD 6670 achieve roughly 17% slower application performance than a stock A8-3870K. However, they offer roughly the same margin of advantage over AMD's APU when it comes to minimum frame rates in games. Average frame rates favor the discrete graphics card by nearly 25%.
Of course, overclocking helps the APU stretch to almost 40% faster than our Pentium processor, and average frame rates pull within 10% of the Intel-based system. That doesn't quite tell the whole story, though. Because the discrete Radeon's advantage was enough to win our game tests, we didn't overclock it. Almost certainly, a little additional tweaking would have pushed the add-in card's performance further in front of the APU's best effort.
What conclusions can be drawn from this data, then? Clearly, the A8-3870K is a better platform for general productivity, particularly when you run threaded applications (or do a lot of multi-tasking) able to leverage four physical cores. The Pentium G620 and discrete Radeon card combine to form a superior gaming system. We used a $140 budget to create as fair of a comparison as possible, but enthusiasts with a little more money to spend on graphics can get even better performance by dedicating additional funds to that subsystem. Meanwhile, the A8-3870K is already AMD's fastest APU, so there's not much room to scale up.
What about overclocking? If you're a value-seeker, eager to push stock components further, the A8-3870K is a fun toy. Asus' F1A75V-Pro motherboard managed to achieve a 3.3 GHz processor clock and 800 MHz graphics frequency through its automatic overclocking feature, and we managed a 3.6 GHz core clock and 960 MHz graphics setting through our own manual efforts. The result was a notable boost to application performance, along with a gaming speed-up that came closer to matching a stock Radeon HD 6670. Intel simply doesn’t have anything in the same price range able to match the A8-3870K’s blend of graphics performance, capacity for threaded apps, and overclocking headroom. It's just unfortunate that overclocking has such a negative effect on the APU's power consumption.
And how about each platform's upgrade path? This is an especially critical point for gamers. Out of six tested titles, two had to be run at 1024x768 in order for us to present playable performance. It's actually fairly impressive that two low-cost configurations can push 720p in most games at decent frame rates. But if you're serious about entertainment, low resolutions will limit the enjoyment you get out of modern titles. At some point, you'll want to upgrade. The good news is that a $120 graphics card is good enough for a smoother experience at 1080p.
But that's where the A8-3870K loses some of its appeal. As we already established, if you're using a Socket FM1-based motherboard and an A8-3870K, your only upgrade would be to a faster add-in graphics card. In that scenario, the APU basically becomes a $140 Athlon II X4. The upcoming Llano replacement, code-named Trinity, is expected to employ the incompatible Socket FM2 interface, so the -3870K could be as good as it gets on Socket FM1.
Perhaps surprising to critics of Intel's interface evolution, LGA 1155 seemingly has room to grow. Not only can you drop a more powerful multiplier-unlocked Core i5 or i7 into it today, but the upcoming Ivy Bridge-based processors should work with existing motherboards as well.
There’s no denying the strength or sensibility of an APU in a compact form factor where value and complexity are closely related. But we're talking about full-blown desktops here. If you're building a general-use desktop PC, the A8-3870K works really well as a low-cost jack-of-all-trades. It does everything fairly well right out of the box, but there's not much of an upgrade path. Rather, if you have aspirations of swapping out components in the future, LGA 1155 is the smarter buy for its ability to support much higher-end CPUs (including a refreshed architecture).