Tuesday, September 10, 2013

New Apple A7 chip may have a Quad-core CPU and tri-core GPU!

Recently Apple introduced iPhone 5S with a new A7 64bit processor. They did not commented much about its specifications. However they do mentioned some comparative factors about performance.

  • GPU performance is 56 times as fast as the original iPhone!
  • CPU performance is 40 times faster than the original iPhone!

GPU Performance

Both these points can be analysed to find number of cores A7 might be having.

As mentioned in Wikipedia, Original iPhone (2G), had a 412 MHz ARM CPU with 103 MHz GPU and 128MB RAM clocked at 137 MHz. These are the basic factors that affect speed of any embedded device.

Lets analyse GPU first.

As mentioned A7's GPU is 56 times faster than iPhone 2G. This implies a raw frequency of 56x103MHz! That is approx 5600 MHz.

Also note that latest A6x has a 4 core SGX554MP4 GPU clocked at 300MHz. In case of PowerVR SGX554 series, each core has 8 graphic units. So A6x has total 32 graphic units clocked as 300MHz. In case of A6, it is 3 core SGX543MP3 GPU running at 266MHz with 4 graphic units per core.

  • Assuming GPU is clocked to 300MHz in A7, we get 5600/300 = ~18 graphic units. (Nearest 16)
  • Assuming GPU is clocked to 266MHz (like A6), we get 5600/266 = ~21 graphic units. (Nearest 24)
  • Assuming GPU is clocked to 200MHz, we get 5600/200 = 28 (Nearest 32)

Rounding to the nearest clock speed with 8 graphics units per GPU core, it could be either a dual core GPU running at 300MHz or a triple core GPU running at 266MHz or a quad core running at 200MHz. Chances of a triple core configuration seems more prevalent, looking at A6.

Conclusion: A7 might be running a triple core GPU clocked at 266MHz or a 4-core GPU clocked at 200MHz.

Now coming to CPU.

As mentioned A7's CPU is 40 times faster. This implies a raw frequency of 40x400MHz! That is approx 16 GHz.

To find the number of cores, we can consider following division factors that directly affect performance:
  • As compared to original iPhone CPU, RAM in iPhone 5 A6 CPU is clocked at 200MHz, giving a factor of 1.8 to 2. 
  • A7 is a 64bit CPU giving it a factor of 2.

So altogether a factor of 4 (2x2) is what we are getting. 

  • Assuming number of cores as 2, we get a clock frequency of 16/(2x2) = ~ 2 Ghz.
  • Assuming number of cores as 4, we get a clock frequency of 16/(2x4) = ~ 1 Ghz.

CPU speed of a quad core configuration comes somewhat same as 1.3GHz dual core A6 chip.

A dual core configuration is also possible if LPDDR3 RAM is used that gives 2x performance gain!

Conclusion: A7 might be running a 4 core CPU clocked at 1- 1.3 GHz with 200MHz LPDDR2 RAM or a dual core CPU with LPDDR3 RAM.

Expected Apple price updates for India after launch of iPhone 5C and iPhone 5S in September 10th Event

Expected #Apple price Updates for #India:

1. C in #iPhone5C was definitely not for Cheap. The price mentioned is $549 (~35k INR) for 16gb.

2. #iPhone5S 16GB unlocked price is $649 (~42k INR).

3. #iPhone4S 8GB is $450 (~28k, with a 10k price drop).

4. #iPhone5 has been discontinued. So around 10-12k INR price drop is expected.

5. #iPhone4 also has been discontinued. Prices will come down to 15-17k INR.

PS: iPhone5 lived like #iPad3 - a half-baked Apple recipe!