[Rumours] Ampe Allwinner Cortex-A7 Quad-core Tablet?

According to latest report the allwinner quad-core is using ARM Cortex-A7 structure. A7 running the same sequence as Cortex A8, it can execute two instructions in sequence in parallel computer, but there are still big difference between A7 and A8. Cortex A7 has an 8-stage integrated pipeline and can support dual-transmitter, but A7 does not support NEON instruction set. They are same in many internal structure but improve greatly in FPU. Limited broadband design make A7 chip volume can be very small. ARM claimed the volume of 28nm’s single-core Cortex-A7 is only 0.5nm²。ARM hope the supplier can set the A7′s die volume to be 1/2 or even 1/3 of A8′s.

Although it is limited in dual-transmitter capacity, ARM hopes A7 can provide more power per Hz performence and overall performance than A8, since it use the more advanced predictor its branch Prediction computing power has improved and this also make the chip more energy saving. ARM also point out that the A7 use more low latency L2 cache(10 cycles), the details should be depends on the manufacturer. In fact, Cortex-A7 should be weaker than A8 in evaluate performance because of the dual-transmitter broadband limitation.

Cortex A7 with Cortex-A15 can achieve 100% ISA compatible, and the A7 able to support new virtual instruction set, integer division and 40-bit memory addressing. It means that A7 can running any codes which running base on A15 core but with lower computational speed. But this make SoC chip equipped with the cortex-A15 and the Cortex-A7 at the same time gain a practical significance, they can switch instantly per the task load. ARM called this mechanism as big. LITTLE. For this part, ARM official website introduces: Cortex A7 and Cortex-A15 are the same in processor system structure and functions set. the difference is that the Cortex-A7 processor’s micro-system structure is more focus on energy efficiency, so these two processor can work together in big. LITTLE configuration to improve the combination of performance and saving energy .

Conclusions: The advantages of the Cortex-A7 compare with Cortex-A8 is higher performance, lower power consumption ,relatively lower cost and compatible with the Cortex-A15′s ISA. The expectation of ARM official website for Cortex-A7 "As a independent processor. It can make period 2013-2014′s less than $100 entry-level smart phone comparable with the $500 high-end smart phone in 2010". So it is worth looking forward to the Allwinner quad-core tablet PC.

Source:
http://www.chinaeshops.com/blog/ampe-allwinner-cortex-a7-quad-core-tablet-is-coming.html
http://www.arm.com/products/processors/cortex-a/cortex-a7.php