In a blaze of glory set to reignite competition in the mainstream desktop market AMD is today launching another APU, the A10-7800. Unlike like A10-7850K which we looked at back in January this APU does not come with an unlocked clock multiplier. But what it does offer is improved performance at lower power envelopes. One of the big advantages of Kaveri over AMD’s prior APUs is its configurable TDP feature. Users can now select whether they want their APU to run within a 95, 65, or even 45 Watt power envelope. This feature has been a boon for enthusiasts trying to build small form factor PCs without resorting to using laptop parts. Instead of merely filling out AMD’s 2014 APU lineup with a lower binned chip this new A10-7800 comes from the factory with a performance optimized version of the cTDP feature found on the A10-7850. According to AMD this means that its latest APU should retain a greater amount of performance as you scale down how much power it’s allowed to consume compared to prior offerings.
We’ve spent quiet a bit of time looking at the comparative power efficiency of AMD desktop and mobile Trinity chips and when AMD launched Kaveri we took a look at the performance differences between the top SKU and the bottom SKU limited to 45 Watts via the cTDP setting. We found that an A8-7600 limited to 45 Watts offered 81 percent of the aggregate performance of AMD top Kaveri chip the A10-7850K. So for an absolute performance loss of about 20 percent you could see double the performance per watt out of Kaveri on the desktop. With the A10-7800 AMD hopes to offer even more performance at those lower power envelopes.
Even according to AMD the gap between the K series Kaveri parts and these non-K cTDP optimised SKUs is small. That said when you limit both chips to 65 Watts the A10-7800 actually outperforms the A10-7850K just a little bit.
With the launch of the A10-7800 AMD is also release the long-delayed A8-7600 which I looked at in January. We’re also getting a new low-end SKU, the A6-7400K. We haven’t had a chance to give the 7400K a once over yet, but rest assured we are working on a review of it.
One of the most interesting things about AMD’s current lineup is how similar all of its APUs are in terms of clock speeds, turbo speeds, and feature sets. In fact is seems that core counts and unlocked multipliers are the biggest differentiators between these SKUs.
AMD is still promoting Mantle even as the excitement around the API seems to have died down a bit. There are a few new games on the market like THIEF, Sniper Elite III, and Plants Versus Zombies: Garden Warfare that now support
(or are going to support) AMD’s graphics API. The performance benefits of using Mantle are palpable but not game changing on mainstream APU hardware. Still the progress that Mantle has made is impressive given that hasn’t even been a year since it was originally announced.
Let’s get the benchmarks. As always our raw data is available on Mega.
There you have it, AMD’s two 78xx chips perform almost exactly the same in their stock configurations. Perhaps there will be a bigger gap at 45 Watts but that’s a story for a different day. As it stands now, picking up an A10-7800 is a great way to get all the performance of a stock A10-7850K and save yourself about $20. Of course that at price point the A10-7800 is lined up right against the A10-7700K which has an unlocked clock multiplier. Thus its hard to make an argument in favor of buying an 7850K when you can get the same feature set from the 7700K or better power efficiency from the 7800 while paying a little less for both and retaining essentially all of the performance that the 7850K has to offer. AMD’s dekstop Kaveri lineup is small and rather homogeneous, and that’s not a bad thing for value conscious buyers.S|A