The Core i7-4950HQ Mobile CRB

At a high level, Iris Pro 5200 would seem to solve both problems that plagued Intel graphics in the past: a lack of GPU hardware and a lack of memory bandwidth. As a mostly mobile-focused design, and one whose launch partner isn’t keen on giving out early samples, it seemed almost impossible to evaluate Iris Pro in time for the Haswell launch. That was until a week ago when this showed up:

What may look like a funny mid-tower from a few years ago is actually home to one of Intel’s mobile Customer Reference Boards (CRB). Although the chassis is desktop-sized, everything inside is optimized for mobile. It’s just easier to build things larger, especially when it comes to testing and diagnosing problems.

The silicon on-board is a 47W Core i7-4950HQ, the lowest end launch SKU with Iris Pro 5200 graphics. The chassis is obviously overkill for a 47W part, but the performance we get with this machine should be representative of any i7-4950HQ system with a cooler capable of dissipating 47W.

If you read our Haswell CPU review you’ll know that Intel tried to be stingy with telling us die sizes and transistor counts for the bulk of the Haswell lineup, electing to only give us data on dual-core Haswell GT3 and quad-core Haswell GT2. Knowing that mobile parts ship without integrated heat spreaders, I went to work on pulling off the i7-4950HQ’s heatsink (after I finished testing, just in case).

With the heatsink off and thermal paste wiped off, I used my bargain basement calipers to get a rough idea of die area. This is what I came up with:

Intel Haswell
  CPU Configuration GPU Configuration Die Size Transistor Count
Haswell GT3e (QC) Quad-Core GT3e 264mm2 + 84mm2 ?
Haswell GT2 (QC) Quad-Core GT2 177mm2 1.4B
Haswell ULT GT3 Dual-Core GT3 181mm2 1.3B

The Crystalwell die measures 7mm x 12mm (84mm^2), while the quad-core Haswell + GT3 die is a whopping 264mm^2 (16.2mm x 16.3mm). Working backwards from the official data Intel provided (177mm^2 for quad-core GT2), I came up with an 87mm^2 adder for the extra hardware in Haswell GT3 vs. GT2. Doubling that 87mm^2 we get a rough idea of how big the full 40 EU Haswell GPU might be: 174mm^2. If my math is right, this means that in a quad-core Haswell GT3 die, around 65% of the die area is GPU. This is contrary to the ~33% in a quad-core Haswell GT2. I suspect a dual-core + GT3 design is at least half GPU.

Crystalwell: Addressing the Memory Bandwidth Problem The Comparison Points
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  • jadhav333 - Friday, July 11, 2014 - link

    Same here johncaldwell. I would like to know the same.

    I am a Blender 3d user and work on cycles render which also uses the GPU to process its renders. I am planning to invest in a new workstation.. either a custome built hardware for a linux box or the latest Macbook Pro from Apple. In case of latter, how useful will it be, in terms of performance for GPU rendering on Blender.

    Anyone care to comment on this, please.
    Reply
  • HunkoAmazio - Monday, May 26, 2014 - link

    Wow I cant believe I understood this, My computer archieture class paid off... except I got lost when they were talking about n1 n2 nodes.... that must have been a post 2005 feature in CPU N bridge S Bridge Technology Reply
  • systemBuilder - Tuesday, August 05, 2014 - link

    I don't think you understand the difference between DRAM circuitry and arithmetic circuitry. A DRAM foundry process is tuned for high capacitance so that the memory lasts longer before refresh. High capacitance is DEATH to high-speed circuitry for arithmetic execution, that circuitry is tuned for very low capacitance, ergo, tuned for speed. By using DRAM instead of SRAM (which could have been built on-chip with low-capacitance foundry processes), Intel enlarged the cache by 4x+, since an SRAM cell is about 4x+ larger than a DRAM cell. Reply
  • Fingalad - Friday, September 12, 2014 - link

    CHEAP SLI! They should make a cheap IRIS pro graphics card and do a new board where you can add that board for SLI. Reply

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