Although our news team reported on the latest AMD APUs last week, we lagged a little bit behind in the review. The chip manufacturer was only able to deliver our kaveri kit a few days after the official launch date, so we have a case of better delay than never. On a positive note, we had more time without a hard time to get on the chip with our numerous benchmarks.
As the successor to last year's Richland APUs, Kaveri has been updated with new CPU cores based on AMD's Steamroller architecture (Richland uses Piledriver cores). The Radeon R7 series GPU has also been integrated, although the 384 SPU version on most Kaveri APUs is not significantly different from the Radeon HD 8670D of the A10-6700 and A10-6800.
Kaveri is AMD's fourth-generation APU, while Steamroller is third-generation CPU technology that is said to be 10% faster per clock and per core than Piledriver. This is achieved by switching the 32 nm high-K metal gate SOI process from Global Foundries to the 28 nm SHP (super high performance) process.
Despite moving from 32nm to 28nm, Kaveri's 245mm2 chip is actually ~ 4% larger than Richland's 236mm2 part, although the transistor density has increased 85% from 1.3bn to a whopping 2.41bn.
On the GPU side, AMD is moving away from the Cayman architecture in Richland, which was first shown in 2010 with the Radeon HD 6000 series. It is replaced by a Hawaii / GCN-based GPU that enables HSA heterogeneous computing.
Kaveri also includes a new memory controller that supports DDR3-2400 and hUMA (heterogeneous unified memory access), allowing the CPU and GPU to access the same memory at the same time. There is also PCI Express 3.0 support that offers up to 24 lanes for better CrossFire performance.
AMD really focuses on gaming performance with Kaveri and believes that the latest APUs have a serious advantage over the competition here. The company's latest processors are used as budget solutions for modern 1080p games, although the Radeon R7 isn't quite up to the task on paper …
Kaveri in detail
Four Kaveri-based APUs are available: the A8-7600 (the model we are testing today), the A10-7700K, the A10-7800 and the A10-7800K. Unfortunately, AMD not only shortened the time of our delivery, but also forgot to include the flagship model. Still, the A8-7600 is probably the best value, so it's a good place to start.
The flagship A10-7850K is a quad-core part that works at 3.7 GHz and a turbo frequency of 4.0 GHz and has a TDP of 95 W. Confusingly, there are two models of the R7, both of which are clearly referred to as the R7. The A10-7850K has the full version with eight GCN processing units (each with 64 stream cores) for a total of 512 SPUs.
The A10-7800 is just another APU with the full R7, and this 65 W TPD part works at 3.5 GHz and a turbo frequency of 3.9 GHz.
The 7700K is also a 3.4 / 3.8 GHz quad-core part, but its version of the R7 only has six GCN processing units, which reduces the number of SPUs to 384.
The same reduced version of the R7 is also included in the A8-7600, which has TDP values of 45 W and 65 W depending on the configuration. The former requires a base clock rate of only 3.1 GHz with a turbo frequency of 3.3 GHz. The 65 W preset essentially overclocked the chip and allowed a base clock of 3.3 GHz with a turbo clock of 3.8 GHz.
Both versions of the R7 operate at 720 MHz, which is considerably slower than the 844 MHz that we saw from Richland's 8670D and 8570D GPUs.
All models also support DDR3-2133 memory and the new Socket FM2 + with chipset support for PCIe 3.0. With Kaveri bringing some pretty significant changes, it's not surprising that a socket update was in order.
The new socket is supported by the A88X chipset. However, since the FM2 + socket is backward compatible with FM2, the older A55, A75 and A85X chipsets will also work if they are used in conjunction with the FM2 + socket. There are two new pins on the FM2 + socket, which means that Kaveri APUs do not fit in FM2. Backward compatibility is good, but FM2 owners would obviously prefer things to be the other way around so they can upgrade to install a new Kaveri APU on an older system.