Topic: Process-invariant hardware metric: hash-meters per second (η-factor) (Read 25021 times)

The package is a BGA, containing a multi chip module. There are 4 dies, each 9mm x 9mm, spaced out by 5mm. The core voltage and frequency vary according to the cooling available to the chip. The chip contains a temperature sensor on die, and increases or decreases the operating voltage and frequency to maintain a target operating temperature at the die. The allows the maximum possible performance to be achieved, given the cooling that is available. In a colder environment the chip will operate at a slightly higher voltage and frequency, and return a higher hash rate than in a warm environment. Simulation runs show that the best silicon will have a TDP of 250W when operating at the name plate (nominal) 400GH/s. Worst case silicon will consume a few % more power to reach this nominal 400GH/s. Note - simulation results can be out by +/- 20%, although they typically come in high (expect lower numbers in real silicon).

I'd like to write today about a small piece of why we are confident our product is better than KnCs.

So today's topic: Our silicon design is superior.

Both are 28nm designs, but HashFast's is far more powerful and energy-efficient.

Let's look at KnC's 28nm ASIC, and some basic details as we can pull from their documentation. https://www.kncminer.com/news/news-25

First let's calculate the hash rate per square millimeter of silicon. This is a measure of the efficiency of the design.

Honestly, we don't need much to estimate this. The lid size for their chip is enough to make some good estimates.
 
KnC's diagram shows their chip has a 41.2mm lid, and implies that the silicon under that lid may be between 30mm x 30mm, and 36mm x 36mm. (The additional space is needed for decoupling capacitors and such.)
    Let's use those two numbers as bounds for the size of the silicon under the lid. If the die(s) take up just 30x30mm of the space under the lid, then:
     30x30mm = 900mm^2
     100 GHash / 900 mm^2 = 0.11 GHash/mm^2

    Or if the die takes up a bit more of the space under the lid,
      36x36mm = 1296mm^2
      100 GHash / 1296mm^2 = 0.077 GHash/mm^2

HashFast's Golden Nonce chip: I don't have to estimate the size because I work at HashFast.
   One 18x18mm die is able to do 400 GHash (nominal - more overclocked**)
   Hashing per square mm:
      18x18mm = 324mm^2
      400 GHash / 324mm^2 = 1.23 GHash/mm^2
   
Let's compare those numbers, for the high and low values for KnC's chip:

      1.23 / 0.11 = 11.2
      1.23 / 0.077 = 16

So HashFast's chip is between 11 and 16 times more efficient, in hashing per square mm, than KnC's chip.

This has an impact on how fast we can deliver units to customers. One wafer of HashFast's chips has the same capacity as 11 to 16 wafers of KNCs. For each silicon wafer delivered by the foundry, KNC will be able to satisfy 11 to 16 times fewer customers than HashFast will be able to. You'll get your units faster once production starts from us.

In addition, the HashFast chip operates much more efficiently. You get four times the hash rate for the same amount of power (250W). (Based on 250W for 100 GHash from KnC, and 250W for 400 GHash from HashFast.)

Calculations such as this are a small part of why we are confident that we are delivering a quality product to our customers.

We figure it's time to start sharing.

Amy Woodward

VP Engineering
HashFast

** P.S. Simon made me put in the line about overclocking. But as per the 'warranty' thread, no one would ever do that to our beautiful chips, right?

https://hashfast.com/hashfast-announces-fastest-bitcoin-mining-chip-in-the-world/


HashFast Announces Fastest Bitcoin Mining Chip in the World!

    Posted on December 13, 2013
    by Janielle Denier   
    in Baby Jet, Blog, Development, Golden Nonce ASIC, News, Rig Assembly   

HALF A TERRAHASH/s (500GH/s) on a single chip.

HashFast ASIC Golden Nonce- Half a Terrahash Complete bitcoin mining system as found in the BabyJet

This result was achieved during the bringup process of HashFast’s GN chip and module. The engineering team are progressively testing the system, and have not yet reached the full speeds the system was designed for. We expect to see better results over the next few days.
This milestone represents a breakthrough in Bitcoin mining technology and is several times faster than existing Bitcoin mining chips. We are starting volume production of mining systems now.
Stay tuned for further speed results.

Well, the problem is that you can have hand-routed designs and other optimizations that only apply at certain feature sizes. Most analogue design work won't carry directly over in a die shrink.

Hrm, doesn't that mean that RISC won out in the end, even though the companies that first introduced it didn't?  So from the standpoint of a product manager deciding whether to fund a RISC project or a CISC project, the right thing to do was to listen to the debates.

All that matters is the real-world performance.