What is Ivy Bridge?

I will talk a little about that second NUC that I mentioned, it is an Ivy Bridge-based NUC DC3217IYE armed with a 1.8 GHz Core i3-3217U, at the time I purchased it represented the lower-end of the performance spectrum. It has an onboard graphics chip on the system board (motherboard) and that is Intel HD Graphics 4000. This is "on-die" which fundamentally means that the graphics processing unit (GPU) is on the same die as the Central Processing Unit (CPU).

So, Ivy-bridge, what does that mean?

Well, Ivy Bridge is the code name for Intel's second generation of Core processors. The previous generation was called Sandy Bridge. I have learned that Intel had what they called a "Tick-Tock" method of processor development and Ivy Bridge had a smaller physical size, and had more processing power than the previous generation.

When I say size, I mean die size, and the Sandy bridge had a die size of 32 nm (nanometer) and the next generation Ivy Bridge was 22 nm. This basically meant that for the same square-millimetre you could fit more transistors because the size of the transistors were smaller than the previous generation.

When I was at training school in the UK, we called them millimetres, not millimeters but regardless there are a million nanometers in a millimeter, so in a square millimeter, there would be 1E12 square nanometers. So, if you reduce the size of the transistor, you can fit a lot more transistors into the same space.

I can be shot down on this one, as I am indeed an "old tech geezer" but my misguided mathematics says that Sandy Bridge, at 32 nm would yield an estimated 1000 million transistors per square millimeter and Ivy Bridge, double that.

It depends on the actual CPU die size as well, so online it says that the die area of Ivy Bridge is 160 mm², it has a total transistor count of 1.48 billion, compared to the Sandy Bridge silicon, which has 1.16 billion transistors crammed into a die 216 mm² in area, built on the 32 nm process. Ivy Bridge has essentially the same layout as Sandy Bridge.

At this point, you're possibly wondering what the point is, but for me, I too am wondering about this "upgrade" and I can demonstrate that it gets worse. I would consider that with all those extra 27.5% transistors there must be an equivalent performance upgrade. So, as an example, my two existing NUCs run on an i3-3217U 1.80 GHz processor, which are Ivy Bridge "third generation" and that processor has a passmark "average CPU mark" score of 2306 and single thread rating of 901 

I do some digging and find it is difficult to find the equivalent low power Sandy Bridge processor which perhaps is something like the i3-2377m at 1.50 GHz which has a passmark of 1824, single thread 722, and an identical TDP of 17 Watts. If I factor the GHz up, that gives me a 1.80/1.50 x 1824 number of 2189 (866 single thread) which only seems to be a 5% increase in power for all that design effort between Sandy Bridge and Ivy Bridge.

Mind you, if we increase the Ghz then the TDP is going to rise, nevertheless, I am going to make my point....

I am sure an Intel boffin would explain the numerous ways that Ivy Bridge is far better than Sandy Bridge, but for the end user, I am sure that we don't expect that a "next generation" processor would only be about five percent increase in processing power than the previous one.

So much for Moore's law.....